Hydronic heating midterm
How much pressure exerted at the bottom of a 28" tall column of water
1 psI
Secondary aquastats should be set.....
10 degrees F over primary no higher than 210
How do we find the required GPM for a hot water system
10 gpm per 10,000 btu output
A PVR is usually factory set to close one pressure rises to......
12 PSI
How much pressure is required to lift water 21 feet
13 pounds Height of system divided by 2.31 ft Plus 4
The aquastat should be set to open it
180-200 degrees F
Backflow preventers should be installed on any boiler installed after.....
1974
How many circuits are usually controlled by the circulator relay
2
At what pressure does a relief valve open on a hot water boiler
30 psi
Static pressure is caused by.....
Gravity
What type of motor is used in the taco zone valves we studied
Heat motor
Which type of thermostat is most commonly used for a boiler
Heating only T-Stat
Fill pressure is determined by
Height of the system
What is the purpose of the flux
Helps solder flow into the joint and seal joint up. helps keep copper clean
What is the required delta T
Hot water boilers 20 degrees F (on test) In real world 20 degrees F plus or minus 5 degrees F
Water is pulled into the eye of the....?
Impeller
Where is a QuickFill bypass installed
In fill line around the PRV
Where is a flue damper located
In the flue pipe above draft diverter
Turning the adjusting screw of a PRV clockwise will...
Increase the fill pressure
What is the purpose of the vent on some backflow preventers
It vents the water out of the boiler
Where is the best location to install a circulator
Just after the expansion tank "pumping away"
One possible disadvantage of a wet rotor circulator is
Limited capacity
What device protects a boiler against dry firing
Low water cut off
What device closes a white Rodgers three wire zone valve
Motor
Wet rotor circulators use water to lubricate the...
Motor bearings
A spring coupler is used to connect the...
Motor shaft to the pump input shaft of an oil lubricated circulator
What must be done to maintain a float type LWCO
Must be blown down regularly
What must be done before soldering copper tubing
Must be deburred, cleaned with plumber sanding cloth, and fluxed
What are two code requirements regarding a paddle type flow switch
Must be used on hot water systems. Must be used on a system where pump operates intermittently
Does the pump effect pressure at the point the expansion tank attaches to the system
No
What is the result of a waterlogged expansion tank
No room for expansion, system pressure rises, relief valve opens, water let out, cold water let in
Air circulating through a hot water hydronic system causes
Noise in the system
The contacts of a circulator relay are
Normally open
Which type of circulator is a B&G 100
Oil lubricated
Which type of circulator is physically larger
Oil lubricated
Name 2 common types of circulators used in hydronic heating systems
Oil lubricated and water lubricated "wet rotor pumps"
Where is the secondary aquastat installed
On the supply line from the boiler as close to the boiler as possible
Where can we find the direction of flow through the system
On the volute
Where is the best place to install an automatic air vent
On top of air separator
What is the advantage of pumping away
Overall system pressure rises the air bubble in the system are smaller this makes the task of removing dissolved air easier
Name two materials used to seal the threads of a pipe joint
Pipe dope , Teflon tape
Which device allows water to feed into the boiler if the boiler pressure drops
Pressure reducing valve
What is the purpose of the expansion tank
Prevents system pressure from rising as water is heated, provides extra space in system for expanding water
Which LWCO feeds electricity into the water
Probe type
What is the preferred method of testing a relief valve
Raise the system pressure above the relief set
Wet rotor circulators do not require
Regular maintenance, a coupling, no bearing assembly, do not need to be oiled
Which device is used to protect the boiler against high-pressure
Relief valve
What should be done with a leaking relief valve
Replace it
What causes an aquastat to open
Rise in temperature
What device is used as a back up to the aquastat
Secondary aquastat
The diaphragm expansion tank uses a flexible membrane to
Separate the air and water
What does the code book say "shall be done" to a relief valve
Shall be tested once a year
A white Rodgers three wire zone valve uses a
Single pole double throw
Why must the probe be kept clean
So it is functioning properly
Which type of flux should be used
Soldering flux
What is the purpose of the hole in the damper
Standing pilot systems
What is the purpose of the backflow preventer
Stop water in the boiler from flowing into potable water supply
Secondary aquastats are.....
Surface mounted switches
Air pressure in the diaphragm tank should be the same as
System pressure
Which terminals in the boiler wire to the end switch
T & T
How does a Honeywell zone valve operate
T-Stat closes calling for heat Zone valve drives the zone open End switch closes
What device can be connected to an air cushion tank to prevent recirculation of cool air saturated water to the system
Tank fitting
Which device in a motorized flue damper proves that the damper is open
The end switch
Which LWCO should never be used on a steam boiler
The flow switch
What device in the boiler is controlled by the flue damper
The gas valve
What component of a circulator moves the water
The impeller
Define pump head
The pumps ability to overcome the system friction and move the water
What device house the impeller
The volute
What device controls the operation of a zone valve
Thermostat
What is the purpose of the QuickFill bypass
To bypass pressure reducing valve
Why is it important to keep the system pressure higher
To keep the air bubbles in the system small doing this allows the air to move through the water instead of lodging in the top of the system. keeping pressure higher improves air separator
What is the purpose of a circulator
To move the water throught the boiler, piping, and radiator. A pump
Why should a tube be installed from the relief valve outlet
To route the water to our safe discharge location
Why should a vent tube be installed on the backflow preventer
To vent the water to a safe discharge location
If delta T is low this indicated that the rate of water flow is
Too fast
What is the lowest permissible water level in a boiler
Top of the lower gauge nut on a steam boiler
And if this cannot be done the valve should be tested by means of the......
Tri lever on top of relief valve
If air is not returned to the tank it will become
Water logged
What type of circulator is a taco 007
Water lubricated
A flow switch type LWCO is a switch that closes when.....
Water starts flowing through the system
When must a flew damper be open
When burners are lit
When does the end switch of a zone valve close
When zone valve is open
When is it recommended to use an automatic air vent
Whenever diaphragm expansion tank is being used
Where is the point of no pressure change
Where expansion tank meets the system
Air enters a hot water hydronic heating system
With the fill water
Can aquastats fail closed
Yes
What part of a zone valve is controlled by a thermostat
Zone valve motor
How can we control the temperature of different zones
Zone valves
What is potable water
drinking water
What type of solder is used primarily for copper tubing
95% tin 5% antim lead free
What is a pump flange
A connection point between the pump and system piping
What type of device is an automatic air vent
A float valve
What is a zone
A portion of building that we wanna heat or cool separately from the rest of the building
What type of switch is a float type LWCO
A switch that closes when water level rises
Code says there shall be no.....
Accumulation of rust or scale that could prevent the free operation of the valve
Installing the tank on the suction side of the circulator ensures that the circulator pressure will be
Added to the static fill pressure
Which expansion tank has the water and air in direct contact
Air cushion
Which expansion tank is the oldest type
Air cushion
Which tank will allow the air in the tank to be dissolved by the water
Air cushion
Which type of expansion tank is hung above the boiler
Air cushion
Name two common types of expansion tanks
Air cushion and diaphragm
What device can be used to return air to an air cushion tank
Air separator
What device controls the maximum temperature of the water in a hot water boiler
Aquastat
List four requirements when installing the tube on a relief valve
it must be routed to floor or a safe discharge. Must be same size as outlet of the relief Has to be installed so cannot be capped Must be made of metal
Where should manual air vents be installed
At the radiators in the highest point of the system
What devices should always be used on a system with a diaphragm tank
Automatic air vent
What is the first device that should be installed in the fill line
Backflow preventer
Name three parts found in a fill line
Backflow preventer Pressure reducing valve Quick Fill bypass
Which of the three parts in the fill line is required by code
Backflow preventer and PRV
Which part of an oil lubricated circulator contains the bearings, seals and pump shaft
Bearing assembly
Why do most residential diaphragm tanks come pre-charged at 12 psig
Because PRV is factory set at 12 psi and PRV and bladder tank work together to maintain system pressure
Why should we never use Teflon tape to seal the threads of the probe
Because Teflon is a insulator
Static pressure in a hydronic system is greatest at the...
Bottom of the system
How would you know if the flow through the system is proper
Check delta T
There should be no water pressure on the diaphragm when
Checking the air pressure
A backflow preventer must be installed on any system that contains
Chemicals
Which 115 VAC load is controlled by the circulator relay
Circulator
What is the first load energized in a hot water boiler on a call for heat
Circulator relay coil
What load in the boiler is controlled by the end switch of a zone valve
Circulator relay coil
Name two loads that may be controlled by the thermostat
Circulator relay coil and zone valve motor
What causes a pressure reducing valve to close
Closes on a rise in pressure
Worn, sagging motor mounts could cause...?
Coupler failure
what type of relay is used as a circulator relay
Double pole single throw with 24 V coil
What is it meant by the term dry fired
Energizing heating source of a boiler with no water in it
How do we find the required pump out for a hot water system
Find longest loop of pipe in the system multiply that length of the longest lose by .06
Name three types of low water cut offs
Float, flow switch, probe type
What path does the electric current take to prove that water is present
From the probe of LWCO, into the water, through the water, to ground
What is meant by G.P.M
Gallons per minute, flow of a system
