g2
6. What size conductor is required to bond gas piping systems to the building's electrical system grounding conductor?
#6 AWG (or larger) copper
(a) If two identical pumps are installed in series, what happens to the system pressure? (b) What happens if the same pumps are installed in parallel?
(a) System pressure doubles (b) System flow doubles
7. At what level must the level of carbon monoxide remain below (on an air-free basis)?
50 ppm
2. What is the maximum length of a metal connector used to connect a gas dryer?
6 feet (2m)
19. What is the allowable clearance to combustibles for a single-wall vent installed on a gas-fired water heater?
6 in (150 mm)
1. What are the allowable clearances to combustibles for a gas dryer?
6 inches from the top, back, and sides of the dryer
7. After the installation checks are complete, how long should the refrigerator run before the customer places any food in it?
6 to 8 hours
3. What mixture drops down the return tube to the absorber tank?
Ammonia and hydrogen vapour
10. What is a zero governor connected to?
An Air-gas mixer in a burner system
6. Powerpiles with outputs of 250 to 750 mV are able to power what?
An appliance combustion safety circuit and its control circuit
Why does an appliance equipped with a draft control device require a larger air supply than one without a draft control device?
An appliance with a draft control device requires extra air for dilution purposes.
What must be done to protect the potable water supply to a hot water boiler?
An approved backflow prevention device is installed in the water supply
What causes condensation?
Cold vents or chimneys and oversized venting systems.
11. Air required for fuel-burning appliances is called _____________________.
Combustion air
6. After the appliance has been checked and repaired, what is done next?
Combustion air and venting system must be checked and prepared for the conversion
10. Water in the combustion chamber is usually a sign of what?
Condensation
4. What will happen if the exhaust tube is not installed properly?
Condensation could build up and drain backward, dripping on and extinguishing the flame
4. Cooling below the dewpoint causes water vapour to _______________________.
Condense to liquid water on a cooling surface
3. How does a gas technician determine how much excess air is being introduced into the combustion chamber?
Conducting a flue gas analysis
6. What are the three methods of heat transfer?
Conduction, convection and radiation
10. How can the total R-Value for a wall or roof be calculated?
Consult R-Value tables and determine the value for each material that makes up the wall or roof, then add the values together.
What must the gas technician do before installing any air cleaner?
Consult the manufacturer's specifications
3. What are three ways to determine the required clearance to combustibles for a range before installing it?
Consult the rating plate, manufacturer's instructions and Code
10. From which vantage point is the motor's direction of rotation viewed?
Front end of the motor
Why is it important to clean the holding reservoir thoroughly?
Fungi, algae, bacteria and viruses may breed in the water and be dispersed throughout the house
7. Name two types of overcurrent protection devices.
Fuses; circuit breakers
12. With what are oxygen and acetylene cylinders fitted to minimize the possibility of explosion in case of fire?
Fusible plugs
7. What units of measurement are used to rate propane-fired stationary engines?
Gallons per hour
3. What happens if the generator flame goes out?
Gas flow continues for 30-40 seconds until the valve closes
6. List the three types of starting relays.
current relays, potential relays, and solid-state relays.
9. A negative pressure in the vent may be caused by:
Improper termination of the vent.
4. Where is the hydrostatic relief valve used?
In a liquid propane system
List at least two problems that can be caused by an improperly-sized duct system.
excessive noise, drafts, incorrect heat rise/drop across heat exchanger or cooling coils, compromised building comfort.
List four problems that might develop in a central furnace if the cooling coil is not kept clean.
increased stack temperature, decreased efficiency, air flow to building reduced, temperature rise increases across furnace
4. A schematic diagram is also known as a ______________.
ladder diagram
What does an oil leak from the coil indicate?
leak must be repaired and unit may need to be recharged
What devices are used to measure pressure drop across the coil?
manometer and/or magnehelic gauge
Where should the test holes for measuring static pressure be drilled?
on the centreline of the coil
3. What two things does a schematic diagram show?
power source; how current flows through the various parts of the circuit
What additional kind of cleaning must be done if untreated water is used as the cooling medium?
scale must be removed
20. Name the three categories of gas pressure regulators.
service regulators, system regulators, and appliance regulators
5. List the four types of single-phase motors most commonly used in the gas industry?
split-phase induction motor, resistance-start motor, capacitor-start motor, and a shaded-pole induction motor.
If there are no viewing ports allowing the technician to view the coil, what must be done?
technician has to cut a hole
How can the external surfaces of a coil be cleaned?
wire brush or fin comb
9. List the seven main reasons for inefficient combustion.
Overfiring of burner; insufficient air floe across heat exchanger; incorrect excess air supply; draft conditions; dirty heat exchanger; incorrect neutral pressure point setting; dirty air filters
Why should flexible duct connectors not be painted?
Paint will make them rigid and inflexible, so they will no longer work to reduce noise
What is the airflow path in an axial fan?
Parallel to the fan shaft.
Describe the basic function of an electronic air cleaner.
Particles are energized by ionizing wires and given a positive or negative charge. Collector plates, negatively charged or charged to ground, attract the particles, which are then removed from the airflow.
9. What is the primary cause of motor insulation failure?
Motor overheating
2. What are the two types of convection heating?
Natural and forced
10. List all approved gasket material for gas systems and why natural rubber is not approved.
Neoprene or other similar material resistant to any action of gas. Natural rubber may dry or crack as it is not impervious to the action of gas.
7. What should you never do when removing or replacing a capacitor?
Never place fingers across terminals of a capacitor.
4. If a liner cannot be installed in a masonry chimney, what must be done to accommodate a gas conversion?
New venting system must be installed
1. Will a conversion to natural gas improve an improperly sized system?
No
10. Should oxygen and acetylene regulators be oiled regularly?
No
12. Will gas flow be interrupted by changing a propane cylinder if an automatic changeover regulator is used on the installation?
No
14. Are revertible appliances recommended for conversion?
No
2. Are all combustion chambers suitable for conversion?
No
2. Can perfect combustion be maintained in a combustion chamber?
No
3. Do the installation and service manuals supplied by the manufacturer always specify details of replacement parts?
No
3. Does a relief valve decrease a regulator's capacity?
No
3. Does cool air contain more water vapour than warm air?
No
3. Is it acceptable to purge a new gas line through the burner system into a combustion chamber?
No
5. Does water vapour remain in the equation when calculating the percentage of CO2 in the flue gas?
No
5. Should exhaust fans discharge into the attic to provide air circulation?
No
6. May chemicals be used in a combination system?
No
7. Does an automatic shutoff automatically reset?
No
7. Is acetylene a very stable gas that is easily compressed to high pressures?
No
8. Are dehumidifiers very effective in winter?
No
8. Can an appliance with a fan-assisted burner vent into a chimney?
No
8. Do all rollout switches have to be manually reset?
No
9. Do HRVs exhaust fresh air?
No
9. Is an external power source required for a control circuit operating on a millivoltage?
No
Can a fireplace burn solid fuel once it has been converted to accommodate a fireplace insert?
No
Do electronic air cleaners remove smoke odours from the conditioned air?
No
If the filter pump is not running, will the pressure switch allow the heater to fire?
No
May a single fan assisted furnace be vented into a tile lined masonry chimney?
No
May chemical additives be introduced into a combination system?
No
Should B vent be used on very high efficiency appliances? Why or why not?
No, because the flue gas temperature is low and the flue products are very wet so gravity venting is not an option.
15. Should the arrow on a regulator body point upstream?
No, it should point in the direction of the flow
4. Does the Base Pressure Index (BPI) correct the test dials? Do the Pressure Factor Measurement (PFM) or Base Volume Index (BVI) correct test dials?
No, none of these meters correct test dials
2. May all types of water heaters be installed in a bathroom? What code clause covers this type of installation?
No. Code clause 7.26.1 of CSA B149.1-05
3. May a draft hood be altered? What Code clause covers this situation?
No. Code clause 8.23.3 of CSA B149.1-05
Is it acceptable to leave water in the heater when the system is winterized, and why?
No. If the water freezes, the tubes may split
8. Is a fan necessary to move the flue gases through a gravity vent? Why?
No. The gravity vent relies on the natural upward movement of heated gases.
4. Suppose the thermostat is calling for heat and you get a reading of 24 V across the lines. a) Is it working properly? b) If it is not working correctly, what is the next step?
No; Replace the thermostat
Are all infrared heaters vented?
No; if the space has adequate ventilation they can be unvented
Are all construction heaters designed to operate on propane?
No; some are designed to operate on either propane or natural gas
3. What is the pressure setting on a relief device?
Not higher than the lowest rated item downstream of the relief device
5. What must the size of the vent piping from a relief device be?
Not less than the vent outlet size of the relief device
3. What must be done to convert a propane dryer to natural gas (or natural gas to propane) to avoid having to get a special inspection?
Obtain a manufacturer's certified conversion kit containing new orifice(s) and regulator part(s)
15. Where would a Unitrol valve typically be installed?
On a hot water heater
1. Where would you find the rated horsepower, the speed, full load amperage and the date code of a motor?
On the nameplate
1. Where is the input rating of a range located and what purpose does it serve?
On the rating plate. It allows the installer to determine correct piping or tubing size, and set burner inputs correctly
When a temperature controller is used on radiant floor system where is the temperature sensor located?
On the supply line about 2 feet away from the mixing point
8. Where are moisture barriers in the building envelope installed?
On the warm side of the insulation
How frequently should furnace filters be inspected in the heating season?
Once a month
2. What is the minimum frequency of a combination system pump cycle?
Once every 24 hours
5. During the lighting of a barbecue should the lid be open or closed?
Open
9. At what pressure are correction factors used when clocking the meter?
Over 0.5 psig (14 inches w.c.)
4. Why is it important to purge the air out of larger diameter pipes with an inert gas prior to the fuel gas being introduced into the pipe?
So there will be no air in the pipe to support combustion
9. How would you clean an orifice?
Soak in non-oily solvent and blow air through it
2. What are the two types of mantles used in gas lamps?
Soft mantles, pre-formed hard mantles
18. What type of armoured cable should be used for installations subject to adverse service conditions?
TECK
6. What causes stack effect?
Temperature difference between inside and outside air
1. What three types of controls work on the principle of thermal expansion of solids?
Temperature disc (Klixon); bimetallic strip; rod and tube
List four properties of air that affect building comfort.
Temperature, humidity, volume and enthalpy (heat content).
1. How long may a cylinder be in use before it must be reconditioned?
Ten years from the date of manufacture
1. An open circuit test or a closed circuit test are used to do what?
Test for a faulty thermocouple.
2. Which meter corrects for temperature and pressure?
The Base Volume Index (BVI)
9. List two sources of regulations and standards of practice that influence decisions concerning airflow in residential construction.
The National Building Code, the Heating, Refrigeration and Air Conditioning Institute of Canada (HRAI) publications.
3. Which meter displays the correction factor on a brass tag?
The Pressure Factor Measurement (PFM)
5. What is a dedicated water heater system used for?
Hydronic radiant heat
What two purposes are served when a combination system is used?
Hydronic space heating and domestic water heating
Why should atomizing humidifiers operate only when the furnace blower is operating?
If the blower is not operating, water will collect in the ducts.
What are two ways in which a mechanical filter could restrict air flow?
If the filter is dirty, or if a thicker filter than the manufacturer has specified is installed.
Why should re-usable filters be re-oiled before they are replaced in the furnace?
If the filter is re-oiled in place, oil could be sprayed on the blower or heat exchanger
How is an automatic vent damper interlocked to ensure it is in the open position before the burner can fire?
The damper actuator has a proving switch that is interlocked with the thermostat controlling the burner
What must be done with the damper when installing a gas log set into a vented wood burning fireplace?
The damper must be locked in the open position
8. What does polarization in an AC circuit refer to?
The difference between hot, neutral and ground
11. What causes a rod and tube aquastat to operate?
The difference in expansion and contraction rates between the copper tube and the invar rod
7. What is the problem with supply-only systems in leaky structures?
They drive moist air into wall cavities
Why can disposable filters not be re-used?
They will not remove particles effectively
9. What controls the downstream pressure in a regulator?
The loading element (usually a spring)
8. Where can specific service information about a gas dryer be located?
The manufacturer's service manual
1. What must be done if a barbecue is converted from one gas to the other?
The rating plate must be changed to indicate what type of gas the barbecue is set up for
What component directs the heat from a low-intensity infrared heater onto the floor?
The reflector
Which two-pipe heating system is easiest to balance?
The reverse return
9. When should the final settings on a bypass valve be done?
When the system is operating at normal temperature and flow values
6. When is a vaporizer usually installed?
When the vapour demand of an appliance is too high for an average size container
17. A 750 mV powerpile should be used when?
When there is a need to power two circuits
10. When should heat ducts be insulated?
When they are installed in unheated or cool areas
12. What is the most common form of electrical conductor?
Wire
2. A map of an electrical circuit is called a ______________.
Wiring diagram
1. What two diagrams are used to determine the specific sequence of operation?
Wiring diagram; schematic diagram
How are the outside surfaces of the reflector cleaned?
With a damp cloth
8. Of what materials are regulator bodies made?
Cast aluminum, cast iron, steel
3. When is a blower cooling relay utilized?
When the system is a combined heating - cooling system
2. The manufacturer's installation and service manual is supplied with every appliance. How much of it should you read?
All of it
7. Which category of furnace is a standard atmospheric appliance ?
Category I
Name two common types of chimney liners.
Ceramic and Metal
7. Once a fan or motor has been cleaned, what are the next two steps?
Check all electrical connections for tightness, then clean the blower compartment
2. What should you do if you notice soot buildup on the baffle?
Check for dirt on orifice, burner venturi, orifice holder, primary air openings. Clean the flue, baffle and burner mesh. If after cleaning there is still a yellow, lazy flame, check for improper gas pressure. If the problem cannot be fixed, contact the dealer or the manufacturer.
13. What controls fluid flow between heating units in a combination system?
Circulating pumps
What are the three general methods used to control temperature zones in a building?
Circulating pumps, zone valves, thermostatic radiator valves
List three types of clearance distances that must be maintained when installing a duct furnace.
Clearance from combustible material, clearance to fresh air intakes and other vents, clearance for service.
Identify three easy-to-fix problems that can restrict air flow through ducts.
Clogged filter, blocked return air grill, blocked cooling coil, clogged blower.
What device controls the operation of a humidifier?
Humidistat
11. On a forced draft burner, where is the fan located?
Located upstream from the combustion zone
Name three problems that can result from operating a forced-air furnace without a filter?
Loss of efficiency, equipment damage, possible fire
9. Frost build up in the attic indicates what?
Moisture problems
6. What is normal purge velocity for large pipes?
200 ft/min
2. What is the number one source of energy loss in most buildings?
Air leakage
Why is air movement an important consideration for building comfort?
Air movement decreases or increases the rate of heat gain or loss from buildings and human bodies.
5. List three controls that can be recalibrated or readjusted in the field.
(any three of the following) Room thermostat, heat anticipator, oven thermostat, gas valve, spark ignition, electrode gaps, some pilots, some solid state control elements
19. The voltage rating of a millivolt thermostat is:
0 to 1.5 V DC
3. The minimum ventilation rate in a room with an 8ft ceiling is what?
0.3 air change per hour (0.3 ACH)
4. State the "rule of thumb" pump sizing formula.
1 gpm for each 10 000 Btu/h input and friction loss of 1 ft for each 40 ft of pipe run
18. What additional controls may be included in a combination gas valve?
100% safety shutoff; pilot gas adjustment; control module
18. Name three types of automatic controls that can be used in instantaneous water heaters.
1. water pressure-drop sensor 2. water flow sensor 3. thermostat in the water heater
14. When the pipe an fittings are set up for welding, how wide is the root gap?
1/16 inch to 1/8 inch
4. If a room is mechanically cooled in summer, what is the ventilation rate required?
1/2 air change per hour (0.5 ACH)
What is the typical range of input of an unvented room heater?
10 000 to 40 000 Btu/h
When reducing the size of a vent connector from that of the draft hood what is the minimum total vent height required?
10 ft
What is the maximum input of an appliance being vented through an exhaust canopy?
120 kW or 400 MBtu/h
8. What three energy sources do three-way refrigerators operate on?
120V, 12V, propane
12. How many Btu are contained in one US gallon of fuel oil?
140 000 Btu
9. How long should a gas range operate before adjusting the oven temperature calibration?
15-20 minutes
What temperature level may be reached with a high intensity infrared heater?
1800°F (980°C)
What is the minimum height a chimney must terminate above the point it penetrates a roof with a 8/12 pitch?
2 ft
What is the minimum height a vent must terminate above a flat roof?
2 ft
6. What is the minimum allowable clearance to combustibles from a gas-fired water heater?
2 in (50 mm)
12. Insulation should be kept how far away from a metal chimney that penetrates the attic?
2 inches
7. What is the maximum setting of a high-limit control on a forced-air furnace?
250 ºF (120ºC)
What is the minimum height a chimney must terminate above a flat roof?
3 ft
4. What is the allowable clearance to combustibles for a range certified for zero clearance?
30 inches above, 1 inch at the back
6. How long does the refrigerator need to be operating before you can check whether it is operating properly?
30 minutes
14. What is the maximum allowable velocity of fluid in supply and return lines less than 2 inch?
4 ft/sec
9. What is the minimum exhaust vent diameter for a gas dryer?
4 inches in diameter
1. What is the minimum size and type of water heater recommended for a combination system?
40 gallon high-recovery or high-efficiency gas-fired water heater
What is the approximately ideal level of relative humidity for optimum comfort in a residence?
40%
Above what input is a low-water cut-off a required component of a hot water boiler?
400 MBtu/h, 120 kW
At approximately what distance from the floor should a thermostat be located?
5 ft (150 cm)
3. What is the allowable maximum total length of supply and return piping?
50 ft
13. Gas efficiency is based on what percentage of boiler horsepower?
75%
2. What percentage of liquid ammonia evaporates into the freezer compartment side of the evaporator?
90%
What is the expected steady state efficiency of an unvented space heater?
90.5 %
21. At what slope should horizontal venting be run?
A 1 inch rise for each 3 ft of run
8. What is the danger in having too little ventilation in a dwelling?
A build-up of pollutants in the air within the dwelling
5. What type of circulating pump should be used in a combination system?
A centrifugal pump designed for use in hydronic heating systems
1. Define "combustion"
A chemical process in which the rapid oxidation of fuel results in the production of energy.
17. What type of system stores large amounts of hot water for intermittent use?
A circulation system
8. How must multiple outlets that are installed in a laboratory (school or other), be protected from leaking gas into the area accidentally?
A clearly marked, readily accessible, master shut-off valve.
Why are cast iron sectional boilers used only in closed loop hydronic systems?
A closed loop system can be quickly purged of air, reducing the risk of corrosion of the cast iron components
2. Thermocouples are used with which type of pilot?
A constant (standing) pilot
4. What measures the system pressure when using a direct- operated relief valve?
A diaphragm
When cleaning the inside of heat exchanger tubes by reaming, what tools are required once the heat exchanger is removed from the heater?
A drill and a carbide-tipped reamer which is the same diameter as the inside diameter of the heat exchanger tubes
Why should static pressure across the coil be measured?
A drop in static pressure beyond manufacturer's suggested limits indicates the unit is not functioning efficiently.
3. On a furnace with no filter rack, what should be done?
A filter rack should be placed in the return air duct where it joins the furnace
11. What type of test is performed to check the polarity of a millivolt meter?
A flash test
To extract heat from flue gases, what would be installed?
A heat reclaimer.
When the flow rate through a pool heater is greater than 125 gpm, what is required to be installed on the heater, and where?
A manual bypass valve between the heater inlet and outlet pipes
8. What is R-Value a measurement of?
A material's resistance to heat flow under static conditions.
7. What tool is used to clean the condenser?
A paintbrush
8. How may fluid flow through combination system components be controlled?
A pressure bypass valve or a shunt pump
When changing an open loop hydronic system to a closed loop system what device is installed to ensure the system is not subjected to unsafe pressures?
A pressure relief valve that is properly sized and has been certified
12. What device is connected to a multiple speed motor to allow for more than one fan speed?
A relay
21. What feature acts as extra protection on a redundant gas valve?
A second shutoff valve incorporated in the valve body
9. What tool should be used to clean the outside of a heat exchanger?
A soft brush
What type of glass is used on a free-standing fireplace?
A special high temperature ceramic glass
What is a spillswitch?
A spillswitch is a device that senses a blocked vent on a draft-hood-equipped appliance.
12. What device is installed in the flue of a residential water heater to improve heat transfer to the water?
A spiral baffle
6. What device would be used if sequenced control was desired for several pieces of equipment?
A time-delay relay
1. What is the normal differential setting on a fan control? Can this be adjusted manually?
About 25°F (14°C). Yes it can be manually adjusted
11. Caulking should be done at what temperature?
Above 5°C
How often should a space heater be inspected and serviced?
Annually, at a minimum
If cells are washed in a dishwasher, why should the drying cycle not be run?
Any contaminants that have not been removed will be baked on if the drying cycle is run, reducing the air cleaner's efficiency.
List the key points that must be considered when determining the air supply requirements for a gas appliance.
Appliance type and location Building construction Appliance draft control
13. To what angle should pipe be bevelled if it is to be welded?
Approximately 37 1/2°
If there are arrows on a filter frame, which way must they face?
Arrows must match the direction of air flow
1. What are the clearances for the top, sides and rear of a gas- fires refrigerator?
As marked on the rating plate
11. How is lime formed inside a water heater?
As the water heats up it becomes less dense and the heavy minerals settle out and begin coating the bottom of the tank.
5. The final drawings on a job are called:
As-built drawings
4. If an appliance rating plate is missing, how can the input be determined?
Ask the manufacturer/distributor of the appliance, or size the burner orifices and check an orifice sizing guide.
4. After welding is completed in an area where combustible material is present, how long should a "fire watch" be maintained?
At least 20 minutes
6. How often should a thermostat be cleaned?
At least once a year
5. How often should a gas lamp be cleaned?
At least once per year
How frequently should filters be replaced?
At least twice a year, and any time they become clogged
4. How much of the insulation value of the wall is on the cold side of the vapour barrier?
At least two-thirds
How frequently should the water holding reservoirs in humidifiers be cleaned?
At the very least, at the beginning and end of the heating season.
10. What are the two main types of conversion burners?
Atmospheric and power burners
What is the major difference between atomizing humidifiers and other types of humidifiers?
Atomizing humidifiers introduce droplets of water into the air. Most other types evaporate water into the air.
19. What is the primary force used to open or close a diaphragm gas valve?
Available gas pressure
Where should an outdoor temperature sensor be placed?
Away from direct sunlight or other heat sources and away from any shielding structures or vegetation
6. Why must there be gas flowing to properly read and adjust pressures?
Because pressure lost due to gas flowing through the system must be included for an accurate pressure reading and it will not be included if the gas is not flowing
5. Why does a gas-fired refrigerator have to be installed level?
Because the unit depends on gravity to move the liquids and gases inside. Running it off level causes these liquids and gases to collect in unwanted areas and not be recycled back to the generator.
Why does a venting system operate?
Because there is draft.
10. On a power-vented water heater, when does the exhaust fan start?
Before burner ignition
2. Describe the first pressure test of the system, before appliances are connected.
Before the appliances are connected, the system shall be tested using air or inert gas. Meters regulators and shut- off valves not rated for the test pressure shall not be connected to the system.
2. A properly functioning pilotstat coil should close the pilotstat valve when the reading on the millivolt meter reads:
Between 2 mV and 5 mV.
11. Where would a four-way valve be installed?
Between the primary and secondary circulating loops
10. What can cause insufficient drying, even if the lint screen is kept clean?
Blocked vent, defective drum seal, blocked air flow in dryer, dryer firing below rated input due to corrosion of dirty orifice
4. How should a gas dryer burner flame look when the burner primary is properly adjusted?
Blue, lively but not too loud, not scrubbing the top of the burner cone (funnel), extending to the end of the cone and tailing up slightly
5. Permanently joining all non-current-carrying metal parts to ensure electrical continuity" is a partial definition of:
Bonding
How is the blower controlled in a free-standing fireplace?
By a temperature-activated switch
14. How is the delivered air volume adjusted if a belt drive fan motor is being used?
By adjusting the pulley or changing the pulley size on the motor or the fan, or both
6. If the type of system and the pressure ranges safely handled by the system are known, how should a relief valve be chosen?
By consulting the manufactures tables
How can smoke odours be reduced?
By installing an activated charcoal filter
How should galvanized pipe and copper be joined together?
By means of a dielectric fitting (generally a union)
8. How is stored water heated indirectly?
By means of a heat exchanger coil located in a boiler, or installed in the storage tank
2. How must the range be connected to the electrical circuit?
By means of an approved power-supply cord with a three-prong grounding plug
8. How is temperature rise determined?
By placing thermometers in the return and supply plenums while the furnace is running
4. How are transformers rated?
By the amount of power the secondary winding can handle
How are the joints on a C vent secured?
By three screws at each joint, spaced 120° apart.
1. With what would you purge a pipe sized over 4 inches, if it has been tested with air?
Carbon dioxide or nitrogen or a mixture of both
Air in the system or low flue gas temperatures can cause what?
Corrosion
In a hydronic heating system, air can cause what three problems?
Corrosion (rusting), insufficient heat output, noise in the system
Which type of wall furnace will reduce heat stratification in a room?
Counterflow type
What damage can a dirty filter do in a system that includes add-on air conditioning?
Decrease operational pressures, causing floodback which damages the compressor
4. What two ways can the stator phase coils in a three-phase induction motor be connected?
Delta or wye
3. List the five steps used when sizing containers.
Determine: the total demand, total effective load on the container, most severe weather conditions in which the container must operate, the correct sizing table. Then select the proper size and number of containers needed.
1. Name two types of displacement meters.
Diaphragm (bellows) meter; Rotary (geared and lobed impeller) meter
16. List the three types of solenoid valves.
Direct acting; lever; pilot operated
5. What types of overpressure protection incorporate a restricting element?
Direct operated relief valves and internal relief valves
What forces of nature have effects on pool heating?
Direct sunlight, wind, shade from trees or structures
7. What type of water heater is most commonly used for residential and low-demand commercial installations?
Direct-fired storage heaters
What is the most common cause of inadequate heating or cooling performance?
Dirty filters
How can clean filters save the customer money?
Dirty filters block airflow, forcing the unit to work harder and use more energy. Blocked airflow can damage the forced-air furnace, necessitating repairs
List three methods for cleaning the cells of an electronic air cleaner.
Dishwasher, soaking, do-it-yourself car wash
Name two advantages of an electronic air cleaner.
Doesn't increase pressure drop: removes small particles more efficiently than mechanical filters.
If a humidifier is used in a system with an electronic air cleaner, where should the humidifier be mounted?
Downstream from the electronic air cleaner
Where must chlorine be injected into the pool circulating system?
Downstream of the pool heater
Which type of air cleaner is usually the most expensive?
Electronic
8. What should be done if welding is taking place in a confined area?
Ensure adequate ventilation.
How frequently should an electronic air cleaner in a residential installation be cleaned?
Every one to six months
5. What are the two sources of moisture problems?
Excess moisture and over cool surfaces
10. Air that is removed from a space and not re-used is called __________________.
Exhaust air
What is the most common cause of flue gas spillage?
Failed control of negative air pressures in a building.
1. Ferrous metals are acceptable for potable water applications. True or False?
False
10. An electrical overload occurs very quickly. True or False?
False
12. A thermocouple must be under load to perform an open circuit test. True or False?
False
12. Control relays are best suited for controlling single-phase pumps of any size. True or False?
False
14. Hot water piping runs should be as long as possible. True or False?
False
14. The maximum current rating of a #10 AWG conductor is less than that of a #14 AWG conductor. True or False?
False
15. Is it acceptable to install relief valve discharge piping in areas that may freeze. True or False?
False
16. Is it acceptable to use steel pipe as relief valve discharge piping. True or False?
False
6. Bonding conductors must be soldered. True or False?
False
5. An exhaust fan system in a dwelling causes a positive pressure due to suction force within the dwelling. True or False?
False, it creates (or can create) a negative pressure within the dwelling.
6. If the dryer burner fires for the first cycle but fails to ignite on subsequent cycles and a solenoid click is heard after the ignitor warms up, what could be the problem(s)?
Faulty booster coil, or faulty holding coil
11. To ensure correct application and selection of a conversion burner, what conditions must be considered?
Firing rate; flue gas travel; combustion or chamber geometry
What is the primary cause of sooting on heat source surfaces?
Flame impingement
12. Names three types of combustion safety controls that rely on flame sensing.
Flame rectifier (flame rod); ultraviolet flame sensor, infrared flame sensor
State the general rule of thumb for sizing circulating pumps.
Flow rate = 1 gpm per 10 000 Btuh input of the appliance, allowing 1 foot of friction loss per 40 feet of pipe run
What is the most serious venting problem?
Flue gas spillage
11. How many air changes per hour are required in a welding shop?
Four
7. Describe what is happening when a flash tube ignites a burner from a pilot.
Gas flows into the flash tube, drawing combustion air with it. Gas and air mix as they travel down the tube to the pilot flame, where they are ignited. Flame flashes back to the burner and ignites the gas at the burner ports.
5. If the dryer burner fires but the drum does not turn, what could be the problem?
Gas supply shut off, or secondary coil is faulty
1. List the four basic components of an absorption refrigeration system.
Generator, condenser, evaporator, absorber
7. What should you do if a cooling unit ruptures and liquid ammonia is splashed on you?
Get fresh air immediately and flush the affected area of your body with plenty of water
1. What are the three factors that must be kept in balance in a gas-fired refrigerator?
Heat input, air circulation, unit leveling
List the four subsystems of a hydronic space heating system.
Heat source, distribution system, heat emitters, control system
5. List the types of personal protective equipment that must be worn when working with or around a welder.
Heavy clothing (free of oil or grease), eye and face protection, gauntlet-type gloves, steel-toed boots, a cap, cuffless pants, and—when required—masks or respirators.
4. Which furnace type is the most popular?
High boy up-flow furnace
5. What type of furnace is used in areas of limited head room?
Horizontal furnace
7. On which types of furnaces would you find an auxiliary limit control?
Horizontal or downflow furnaces
On fire tube boilers, which passage design results in more efficient heat transfer?
Horizontal passages
8. Where is the information on installation clearances for tanks and cylinders?
In the appropriate codes
Where is the circulating pump in a hydronic system located?
In the supply main, just downstream of the expansion tank
6. In which position will the switches and other devices in a circuit be shown in if a wiring diagram is drawn in the "at rest" state?
In their normal positions (normally-open or normally closed, depending on their function)
13. Where and how should temperature sensors be mounted?
In wells, or fastened directly to metal pipes, and according to manufacturer's recommendations
8. A causes of negative pressure in a building is:
Inadequate ventilation in the building.
5. Air flowing in through openings is called ______________________.
Infiltration
5. What is the formula for determining effective load?
Input rating x Load factor
7. If a masonry chimney is too large, what must be done?
Install a liner in the chimney
5. Who is responsible for a safe and efficient conversion?
Installer or installing contractor
2. On small refrigerators, what are your options if a top- mounted vent is not possible?
Installing an upper side vent
1. What is a major factor in a building's energy conservation besides air leakage?
Insulation
13. List the three main types of control modules.
Intermittent pilot; direct spark ignition; hot surface ignition
How is an immersion-type low water cut-off tested?
Interrupt the electrical circuit to check that the burner shuts down
11. What advantage does a circuit breaker have over a fuse?
It can be reset instead of having to be replaced
3. List the adverse effects from ultraviolet radiation produced by arc welding.
It causes burning of unprotected eyes and skin. Eyeballs and skin may blister. These conditions may last hours or days.
5. If the pressure of a gas increases and its temperature remains constant, what happens to the volume?
It decreases
7. When flow rate increases through a regulator, what happens to the downstream pressure?
It decreases
List the three purposes of the blower on a pulse combustion blower.
It draws in outside air for combustion on start up, it pressurizes the air cushion chamber, it purges the combustion chamber of residual flue gases
6. If the temperature of a gas is increased and its volume remains constant, what happens to the pressure?
It increases
7. If the temperature of a gas increases and its pressure remains constant, what happens to the volume?
It increases
9. What is an operating pressuretrol?
It is a normally closed switch that controls the pressure in a steam boiler. It opens when the set pressure is reached, shutting off the gas supply to the burner.
8. What is an operating aquastat?
It is a normally closed switch that controls water temperature in a boiler. It opens when the temperature setpoint is reached, shutting off the gas supply to the burner.
9. If a building is pressurized, what happens to the excess air?
It is forced out through any openings in the building envelope
How is average stack temperature determined?
It is the average between the temperature at the flue collar and the temperature at the vent termination.
12. What is the disadvantage of oversizing a furnace?
It is very inefficient
What can happen if the electronic air filter is turned on when cells are wet?
It may not work. Some EACs will not function until cells dry. If it does work, arcing and sparking may occur.
1. Before a conversion is undertaken, what must be done to the boiler?
It must be inspected for cracks or loose cement in the heating sections, warped doors and door frames, and any other defects that would allow uncontrolled air leakage into the combustion chamber.
If a check valve chatters, what must be done?
It must be replaced
4. What must be done to piping or tubing passing through concrete?
It must be sleeved, coated, or double-wrapped.
6. What is the AFUE rating of a typical medium efficiency (mid-efficient) furnace?
It ranges from 78% to 82% efficient
7. How would you recognize a manual shut-off valve as being approved for installation in a natural gas or propane system?
It shall be of the plug, ball or eccentric type and shall not be subjected to greater temperature or pressure greater than its rating.
If the power pack is not working, what should be done?
It should be replaced
What is the function of a spillswitch?
It shuts off the burner when spillage is detected.
If excessive dust in a building is coming from the humidifier, how can it be identified?
It will be white, since it consists of mineral deposits.
3. Insulation is measured by?
Its thermal resistance value
6. List two important safety precautions to be observed when working with an oxygen cylinder.
Keep oil and grease away from the oxygen and never attempt to repair a faulty cylinder.
2. List the seven steps to be taken when troubleshooting.
Know the system; ask questions; evaluate your information; make a trial run; re-evaluate available facts; test your conclusions; correct the conditions
8. List the four main reasons for the formation of carbon monoxide.
Lack of excess air; poor burner mixing; flame impingement; cracked heat exchanger
3. The temperature of emissions from gas firing are (more/less) than the temperature of emissions from oil or solid-fuel appliances.
Less
4. What voltage usually operates the fan control?
Line voltage
8. Which pressure applications are automatic shutoff valves designed for?
Low and high pressure
15. Insulated butt splices are recommended for what type of connections?
Low-voltage wiring connections
1. What is the maximum allowable pressure downstream of a pressure controlling device?
Lowest maximum pressure rating of downstream equipment, regulators or piping
13. What is done to keep the air balanced in a building?
Make sure the amount of air entering the building is the same as the amount of air exiting
14. What instruments are used to test for depressurization of a building?
Manometer or Magnahelic gauge
List four common air elimination devices used on a hydronic heating system.
Manual air vents, automatic air vents, air purgers, microbubblers
17. What does a basic combination gas valve include?
Manual shutoff valve; automatic gas valve; pressure regulator
5. Which two documents must be adhered to if you replace a fan control?
Manufacturers' instructions and the Electrical Code
1. Define insulators.
Material that resists heat conduction
6. What are the four elements of a direct operated regulator?
Measuring element, loading element, restricting element, atmospheric vent
Which type of air cleaner is usually the least expensive?
Mechanical
What two types of drive heads can be used on a thermostatic radiator valve?
Mechanical or electrical
Name three types of air cleaners that can be used with a forced-air furnace.
Mechanical, electrostatic, electronic.
Name two common problems that can result from water overflow from a humidifier.
Mildew and corrosion in the ducts
13. What does a closed-circuit test show?
Millivoltage that can be maintained under load
4. What two things are installed for moisture control in a building?
Moisture (vapour) barriers and ventilation
14. List the basic sequence of operation for a control module.
Perform a safe start check; ignite the flame; power the gas valve; prove presence of flame; monitor flame during burner cycle
9. Matching the polarity of the primary and secondary sides of a transformer is called ____________________.
Phasing
10. What could be the causes of intermittent pilot outage on a range equipped with a mini-pilot system?
Pilot size inadequate, weak magnet, overfired or smothered main burner flame causing smothering of pilot
4. What must be used to test a combination system?
Potable water only
What are the four components of an electronic air cleaner?
Prefilter, power supply, ionizing wires, collector plates
What can be done to correct over-firing?
Pressure adjustments and/or burner orifices can be changed
Why are air cleaners installed ahead of heating or cooling coils and air conditioners?
Prevent the units from getting dusty and increase their efficiency.
"The pressure difference produced by a pump between its inlet and outlet ports" is a partial definition of what?
Pump head
13. What five factors need to be considered before selecting a regulator?
Rate of flow, type of gas, inlet gas pressure, outlet gas pressure, piping size
7. If the thermostat on the control unit is more than 20°F off setpoint, what should you do?
Recalibrate it.
What two purposes do duct liners serve?
Reduce sound, minimize heat transfer.
Define relative humidity.
Relative humidity is the percentage of moisture in air compared to the percentage of moisture it would hold if it were saturated.
2. What are the most commonly used overprotection devices?
Relief Valves, Monitors, Automatic shut-off
3. Suppose that upon testing a furnace, the fan motor will not run. The burner is operating, the heat exchanger temperature is above the fan-on setpoint and the fan switch contacts are open. What should you do?
Replace the fan switch
5. If cracks are discovered in the heat exchanger of a furnace, what must be done?
Replace the heat exchanger
What two things must be known before the correct-size blower can be chosen for a building?
Required air flow rate for the building, total static pressure drop for the system.
Name three factors that may be present in a home that would suggest cleaning must be more frequent.
Residents who smoke, pets, hobbies such as woodworking
12. Recirculation air removed from a space is called _______________________.
Return air
6. What would be temperature of the flue gas if an appliance was 100% efficient?
Room temperature
6. If a control unit is sticking in the ON position, what should be done?
Rotate the dial on and off a few times. If still sticks, replace it.
2. What are three categories of gas pressure regulators?
Service regulators, system regulators, appliance regulators
14. What is meant by the term "gangable box"?
Several boxes may be joined or "ganged" together
Which is the simplest hydronic distrubution system?
Single series loop system
11. List the three types of bearings used on the rotor shaft
Sleeve bearing; ball bearing; roller bearing
5. What is an alternative to completely purging long, large pipes with nitrogen?
Slug-purging
Why must the sides and front of a space heater be free from obstruction?
So combustion air can enter freely
When vent capacity is exceeded, what happens?
Some products of combustion spill from the draft hood of the appliance.
2. What are the two main parts of an electric motor ?
Stator and rotor
Which type of control valve will provide an infinite number of firing rates between low fire and high fire?
Step-modulating control valve
2. List the factors that affect the vaporization rate of propane in a propane cylinder.
Surface area of the tank, ambient temperature, temperature of the gas, level of liquid propane in the cylinder, relative humidity, location of the tank
5. What are the most common auxiliary devices found in control systems?
Switches
2. What conditions occur when purging is not carried out correctly?
The accidental explosion of a gas-air mixture outside and inside the pipe.
2. What is solar gain?
The amount of heat gained by a building because of the exposure of its exterior walls and roof, windows, and doors to sun.
4. On what does the amount of cooling depend?
The amount of heat produced by the burner flame
Why might an appliance installed in a laundry room corrode more readily than one installed in a room on its own?
The appliance may use combustion air which has been exposed to bleaches and be contaminated.
Incomplete combustion and very high stack temperatures may indicate what?
The boiler is over-firing
1. "The floor slabs, foundation, walls, roof, windows and doors" is a definition of what?
The building envelope
2. What is condensate drain piping used for?
The condensate drain piping is used to drain all liquid waste produced by the combustion process.
15. Where the possibility of physical damage to a conductor exists, what must be done?
The conductor must be adequately protected
10. Despite similarity in outward appearance to those of a light switch, how are the contacts in a toggle motor starter different?
The contacts in a toggle motor-starter are horsepower- rated, and the contacts in a light switch are rated for the amount of current they can handle.
5. What system supervises the operation of gas-fired equipment?
The control system
Why does a copper fin tube boiler require less surface area to transfer heat than a steel fire tube boiler?
The copper tube has a higher thermal conductivity than steel tube
What must be done if a gas log set is installed in a fireplace that is equipped with glass doors?
The doors must be fully open when the log set is operating
On an appliance with forced draft, where is the draft produced and by what?
The draft is produced upstream of the combustion zone of the appliance by a mechanical device (usually a fan).
3. What does a thermocouple power when it is being heated?
The electromagnet in the safety shut-off or safety switch
2. State the adverse health effects from exposure to welding X-ray equipment.
The equipment emits ionizing radiation by way of Xrays and gamma rays which can cause extreme damage to unprotected parts of the body.
10. If the absorber is hot and the generator section is warm, what does this indicate?
The evaporator is blocked
Which component of a hydronic heating system is installed to keep the pressure in the system stable as the water temperature increases?
The expansion tank
9. What acts as the heat exchanger in a direct-fired water heater?
The flue
5. What should be done if a customer shows signs of CO poisoning?
The furnace should be shut down and the building ventilated. Then a proper analysis of the flue products and the supply air should be conducted
1. When installing gas-fired water heaters, who is responsible for following Code requirements?
The gas technician
Who is responsible for inspecting an existing chimney before it can be used to vent a gas appliance?
The gas technician
Which type of valve is best suited for throttling flow?
The globe valve
Which is preferred: a horizontal vent manifold or one which is steeply sloped?
The horizontal
What are the three major components of the House-as-a-System?
The house itself, the mechanical equipment, the occupants
Which hydronic distribution system uses diverter tees to divert main water flow through the heating unit?
The one-pipe system
9. What will cause the burner to shut down if there is a blockage in the vent?
The opening of the pressure switch
5. How is a burner orifice cleaned?
The orifice is soaked in a non-oily solvent and then air is blown through it
20. Why should you not solder a fitting directly onto the cold water inlet of a water heater?
The plastic dip tube inside the cold water inlet could melt
Which pool component is most likely to corrode and why?
The pool heater. Minerals in high concentrations precipitate out of the pool water, forming deposits in the heat exchanger tubes.
4. What is a plenum?
The portion of the ductwork system connected directly to the furnace
What must be done before opening the blower door on a forced-air furnace?
The power must be disconnected
How can you tell if a differential pressure bypass valve is working correctly?
The pressure at the discharge side of the pump will not increase as zone valves close
2. Who is responsible for piping downstream of the meter?
The property or building owner
What three problems may be caused by relative humidity that is too low?
The room may feel cooler than its actual temperature. Static electricity will increase. Occupants may be more susceptible to colds and other viruses.
When sizing the vent for a high altitude installation which rating is used when determining maximum capacity?
The sea level rating
6. When adjusting the minimum heat input, what two things do you look for?
The setting is low enough to prevent over-cooling and not low enough to allow the flame to be blown out by drafts.
What damage will be evident on the belts in a belt-driven blower if the pulleys are not aligned properly?
The sides of the belt will be worn.
When the vent tables permit more than one diameter of pipe that can be used for a connector or the vent which is preferred: the larger or smaller?
The smaller
11. Relays are magnetically operated on which principle?
The solenoid principle
8. What is a sigh that the refrigerator should be defrosted?
The space between the evaporator fins is more than half filled with ice
If an appliance that is equipped with a draft control device is installed in an enclosure within a structure, and air for combustion is taken from the structure requiring addtional openings, where must the openings be located?
The upper openings should be located as near to the ceiling as possible, and never lower than the lowest draft control device. The lower opening should be located between 6 inches and 18 inches above the floor.
1. If the venting on a high efficiency furnace runs through unheated spaces, what must be done?
The vent pipe must be insulated
How is the available height determined on multi-storey vent installations?
The vertical distance between the highest draft hood or flue entering that segment and the centre line of the next higher inter-connecting tee is measured
2. What causes the fan to shut off under normal operating conditions?
The warp switch inside the fan control cools down enough to open the circuit to the fan
What happens to the water vapour in the combustion products if the flue gases are cooled below the dew point?
The water vapour condenses into a liquid state
10. If a dot is shown where wires cross on a wiring diagram, it means __________________.
The wires are connected
What should be checked first if an aquastat appears to be malfunctioning?
The wiring connections and electrical contacts in the aquastat
9. Which type of monitor, wide-open or working, is less likely to have operating problems? Why?
The working monitor, because it is operating all the time. The wide-open monitor may become slow or damaged because of inactivity.
4. What is wrong if you notice a yellow substance on the tubes?
There is a leak in the absorption system
What are the usual maximum settings of the operating and safety controls on a pool heater?
Thermostat (aquastat) 100°F High limit aquastat 140°F
6. Give three examples of operating controllers.
Thermostat; operating aquastat; operating pressuretrol
9. Joints in steel piping used in gas systems shall be:
Threaded, flanged or welded.
Why would a cooling coil be added to a forced air furnace?
To allow the forced-air furnace to function as a central air conditioner.
4. What is the purpose of performing a flue gas analysis after setting up a conversion burner?
To check combustion efficiency and for safety
What is the purpose of a thermal balancer?
To delay circulator shut-off by 60-90 seconds after burner shut-off, so residual heat in the boiler may be distributed and temperature in the system balanced with the boiler temperature
8. What are the test dials on a meter used for?
To determine input to appliances and to indicate any downstream leaks in the gas piping
6. Describe the function of a solenoid valve.
To energize (open) on a call for heat and de-energize (close) when the heat demand is satisfied.
8. Why is it important to keep the condenser and absorber fins clean?
To ensure adequate air flow for cooling purposes
2. Why is a smoke test performed?
To ensure combustion is air-tight
8. Why is it important to verify the calibration of an oven control?
To ensure safe and efficient operation and satisfactory
1. What are mantles used for?
To give off light
5. Why is it important to keep the flue clean?
To improve the heat transfer required for proper refrigeration; to reduce gas consumption; and to avoid incomplete combustion and the generation of carbon monoxide
3. Once the furnace is installed, what are the gas technician's responsibilities to the user?
To instruct the user on proper use of the furnace, and to leave the operating instructions with the user
7. How should three-way valves be sized?
To match the flow requirements of the heating unit supplied by the system
Why is it important in airtight buildings that the combustion air supply for a gas appliance work in conjunction with any air - exhausting equipment?
To minimize the effect on appliance performance and ensure the health and safety of the occupants.
What is the purpose of balancing valve?
To modulate or balance the flow to each branch in the hydronic system
8. What is the purpose of an overload device?
To protect the motor from overheating
6. What is the main function of the orifice housing?
To provide a correct air-gas ratio
5. What is the purpose of the appliance regulator?
To reduce gas supply pressure to operating pressure of the appliance
1. What are the two main purposes of gas pressure regulators?
To reduce the supply main pressure to the house pressure and to maintain a constant downstream pressure regardless of the changes in flow rate
13. What must a fan motor be capable of?
To start the fan rotating and rotate it at maximum operating speed without overheating
What is the purpose of a tip-over switch on a construction heater?
To stop the flow of gas if the heater is tipped over
What is enthalpy?
Total heat contained in a substance.
6. The surest way to identify contents of a sealed pipe is to:
Trace it back to its source.
1. Wood is a form of biological pollution. True or False?
True
12. Carbon monoxide is tasteless and odourless.
True
20. Total electrical resistance in a system includes the heat anticipator in the thermostat. True or False?
True
3. A storage-type water heater may be used in a fan-coil combination system. True or False?
True
3. Loose wiring causes increased resistance.
True
4. Before starting any repairs, what should you do?
Turn off the gas supply and allow the glass to cool
10. How is a pressure switch tested to see if it is defective?
Turn off the power to the furnace and remove the electrical leads from the switch. Connect a meter across the switch and if there is continuity, the switch is defective.
2. A high efficiency furnace incorporates how may heat exchangers?
Two
11. What type of regulator arrangement is required in propane installation?
Two Stage
Which vent type is capable of withstanding the highest flue gas temperature?
Type A vent
What type of vent is used with a recessed wall furnace?
Type BW
Which type of vent is used in a conventional wall furnace?
Type BW
Where is the draft relief opening typically located on a room heater?
Under the hood at the back of the unit
7. What percentage of total heat loss does the basement account for?
Up to 35%
3. Name the two parts of the vent system commonly used in recreational vehicles.
Upper and lower vents; sealed and combustion vent
8. To improve energy efficiency of windows, what can we do?
Use weather stripping or install double- or triple-glazed windows
What is the only recommended procedure for cleaning heat exchanger tubes that does not require removal of the heat exchanger?
Using a wire brush to clean the exterior of the tubes
List at least three factors that affect the heating/cooling load of a building.
Variation between indoor/outdoor temperature, infiltration of outdoor air, ventilation of internal air to outdoors, internal temperature variations caused by lighting, people and their activities, appliances, etc.
What three factors must be included when air flow in a building is calculated?
Velocity of the air, volume of air moving through ducts, effects of friction.
2. The circulation and purification of air in an enclosed space is a definition of what?
Ventilation
What can happen if ionizer wires are broken?
Visible arcing and sparking
1. State a Code practice during installation of piping and tubing that will ensure the system stays leak- free for years to come.
Visually inspect pipe, tube and fittings.
Which unit is more useful for measuring very low pressures? Inches mercury column or inches water column?
Water column inches.
3. When and Where would you perform a soap test?
When a leak is indicated by a drop in pressure, every joint and fitting must be checked.
Under what conditions can a gas appliance be installed in a building and not have a separate combustion air supply?
When it is a non-airtight building and the volume of the building is sufficient.
When is a chimney considered to be an exterior chimney?
When one or more sides is exposed to the outside
When will draft be greatest?
When the average stack temperature is greatest; When the outdoor air temperature is least; and When the stack height is greatest.
On three and four way mixing valves where does the mixing take place?
Within the valve body
3. What is the difference between a wound rotor motor and squirrel cage induction motor?
Wound rotor motor has insulated windings
5. If manifold pressure is correct and clocked input is incorrect what could be the problem?
Wrong orifice size
1. Must all defective heat exchangers be replaced immediately?
Yes
10. 11. Is a thermocouple considered to be a combustion safety control?
Yes
14. Is operating temperature a factor when installing propane cylinders in a system?
Yes
2. Is a shutoff valve necessary when using a quick disconnect device?
Yes
3. Can barbecues equipped with piezo ignition be match-lit?
Yes
3. Is a clothes dryer considered to be a part of the mechanical systems in a building?
Yes
3. Is a water test required on the boiler?
Yes
4. Does the flue outlet have to be plugged before a smoke test is preformed?
Yes
4. Is it possible to install insect guards on burner tubes?
Yes
5. May a sleeve installed in pavement to allow free movement of the pipe also serve as a vent pipe inspection point?
Yes
6. Does the replacement fan control have to be the same as the one being replaced?
Yes
6. Should an attic be ventilated?
Yes
7. Can a building's air flow be altered by the installation of a furnace with an induced draft?
Yes
7. Upon inspection, the pilot flame of a powerpile-equipped appliance is observed to be blue in colour, burning steadily, and contacting the top 0.5 inches of the powerpile tip. Is this acceptable?
Yes
9. Are high efficiency furnaces power vented?
Yes
9. Is a draft control device required to be in the same room as the appliance?
Yes
Are the combustion products of a construction heater vented into the heated area?
Yes
Can the installation of air vents help prevent pump cavitation?
Yes
May a fan assisted furnace be vented into a masonry chimney that is serving a draft hood equipped appliance?
Yes
May a wall furnace be installed directly on a wood floor?
Yes
Will the thermostat anticipator setting change if more than one baseboard heater is wired to a single thermostat?
Yes
15. Are inshot burners accepted for use in a Type B combustion chamber? If so, under what conditions?
Yes, as long as the combustion chamber liner and insulation are installed
7. Can back-drafting cause spillage of flue gases? If so, could it be dangerous and why?
Yes, because it could include carbon monoxide
May a baseboard heater's electrical supply be plugged directly into a wall receptacle?
Yes, provided it is equipped with a pre-assembled power cord
Do the people in a building contribute to heat gain?
Yes. Both the number of people and their activities generate heat.
6. Must an appliance be thoroughly cleaned before conversion? What is the Code reference?
Yes. Clause 7.6.2 of CSA B149.1-05
10. Can a three-way valve be used as a diverter? If yes, where?
Yes. On the return line.
1. When troubleshooting gas-fired equipment, is it necessary to look at other systems besides the burner and controls? If so, which ones?
Yes. wiring, air supply, fuel supply, and characteristics of the flame
7. Are position and location important factors for thermostat installation? If so, what are the requirements?
Yes; it should be placed in a room that has an average temperature of the dwelling, exposed to normal air circulation, approximately 5 ft from floor, not near heat elements such as lamps and direct sun, and on an inside wall.
3. What must you be sure of when installing indoor gas lamps?
You must be sure that the room is properly vented
9. Name the two principles of effective air filtration in the building industry.
a) Arrestance b) Dust spot efficiency
5. What two functions do automatic valves perform?
a) Control, firing of the burner b) Safety shut-off
6. Name three terms used to describe ventilation distribution systems.
a) Dedicated (independent) b) Integrated (combined) c) Through-the-wall
1. What size is the tracer wire (a) on underground gas piping? (b) What material is it made of?
a) Minimum 16 gauge b) Copper
10. Cracks and penetrations on exterior walls should be sealed where, and with what?
a) On the inside surface of the wall b) With caulking
1. The three general categories of major welding hazards to workers in the vicinity of welding operations are:
a) Physical b) Chemical c) Environmental
3. Coatings on underground steel pipe are made of (a) what material; and (b) in which colour(s)?
a) Polyethylene b) Yellow or Blue
7. All control valves open and close in response to changes in what?
a) Temperature b) Pressure c) Humidity d) Fluid Flow
6. List three methods of identifying gas piping inside a commercial or industrial building.
a) The entire system shall be painted yellow. b) The system shall be provided with yellow banding. c) Utilizing yellow labels, the system shall be marked "Gas" or "Propane"
4. The two ways that manual valves are joined to the gas piping systems are:
a) Threaded b) Flanged
4. Above-ground gas piping shall be identified by one of which two methods?
a) Yellow paint or b) Yellow banding
8. Three things that can cause a small, blue pilot flame are:
a) a small or restricted orifice b) low gas pressure c) a clogged pilot filter
9. Two situations that cause overcurrent are:
a) a surge in current when a motor starts up b) a short circuit
7. The two most common devices for the protection of electrical systems are:
a) fuses b) circuit breakers
4. What portion of the hot junction should be heated by the pilot flame, and what should the temperature difference be between the hot and cold junctions?
a) the first 0.375 to 0.5 inches of the tip b) at least 400°F (204°C)
14. During a pilotstat coil test, at what point and at what mV reading should the coil drop out?
a) within 90 seconds b) between 2 mV and 5 mV
What adjustments should be made if the pressure drop across the coil is too great?
adjust blower speed to get the correct volume
