HPSV exam
What does a test of the compressor mineral oil after a burn out indicate?
A. Acidity
What describes the airflow path of an outdoor pull through coil?
A. Air moves from the outside to the inside of the coil
what condition can cause a reduction from design capacity in a heat pump?
A. An undersized vapor line
In a heat pump refrigerant circuit, and open check valve is used to:
A. Bypass refrigerant flow around a metering device
In an economizer system, when the outdoor air enthalpy exceeds set point, the outdoor air damper:
A. Closes to a preset minimum position
If the technician believes that a hermetic Compressor has a permanently open internal overload protector, the technician should test the compressor while it is:
A. Cool
The component used to reduce sound transmission and prevent water leaks of a package heat pump installed on a roof is the:
A. Curb gasket
Liquid line flash gas can be caused by which of the following?
A. Excessive liquid line length or lift
A suction line accumulator should be used in a residential heat pump only when recommended by the manufacturer is:
A. Long refrigerant lines increase system charge over recommended maximum charge
The technician suspects that an outdoor thermostat used to bring on auxiliary he may be out of calibration. The thermostat is a close on fall type that is adjustable. One method for checking the thermostats calibration is to:
A. Manually rotate the shaft until the thermostat closes and compare the dial setting to an accurate outdoor temperature reading +10°F
Which of the following are temperatures used by electronica demand defrost controls?
A. Outdoor coil and outdoor air
What are the first two checks typically made an electronic control?
A. Presence of proper input signals and proper output voltages
Which of the following is the sensible heat ratio?
A. Sensible heat removed divided by total heat removed
Thermostatic expansion valves meter refrigerant flow to a coil to maintain
A. Super heated refrigerant leaving the coil
A technician checks a package heat pump operating in cooling and find the following conditions: The unit has a piston type metering device on both the indoor and outdoor coils, outdoor temperature 75°F, superheat 55°F what is the diagnosis and corrective action?
A. The unit is low on charge and charge needs to be added
What is an important reason for using electronica defrost controls?
A. They provide more accurate control
A technician finds a compressor contactor energized, but the compressor is not running. To troubleshoot, the technician should check the proper:
A. Voltage to the load
To properly check in energized compressor circuit the technician should use a multi meter set for:
A. Volts
The continuity of a fuse in a disconnect should be tested by checking resistance:
A. With power off
The coil of a potential relay is connected to which terminals of a single stage compressor?
A. common start terminals
What is the recommended total external static pressure used for heating and cooling equipment with blowers for 5 tons of cooling or less (excluding high velocity)?
B. 0.5 IWC
It technician measures the return air temperature of 100,000 BTU output furnace to be 65°F and the supply side air temperature is 135°F. what is the SCFM(standard CFM)?
B. 1323 SCFM
Manufacturers recommend noncommunicating thermostat wire used in residential applications should not be less than:
B. 18 gauge AWG
The voltage most often used to power the outdoor unit in a residential system is:
B. 240 V single phase
R-410A Vapor in line diameters with links 50 feet or less are typically specified for a vapor pressure drop that does not exceed what value?
B. 3 psi
What is the sub cooling temperature for an R-22 unit with a high side pressure of 260 PSIG, a low side pressure of 68 PSIG, and a liquid line temperature of 90°F
B. 30°F
What best describes an extended Plenum duct system?
B. A single sized trunk extending in one or two directions with many branch ducts
Which of the following is used to make accurate residential loan calculations?
B. ACCA manual J
What is the effect on supply airflow using a PSC blower motor when static pressure on the return is eliminated
B. Airflow will be increased
An electronica room thermostat without remote sensors may have a feature that allows:
B. Controlling of multiple zones
Why do some electromechanical type thermostats require connections to both the hot side and common side of the low-voltage transformer?
B. Display lights must be powered using using both sides of the line
What type of blower is most commonly used in an indoor residential unit?
B. Forward curved centrifugal fan
To properly set a heat anticipator it is necessary to check the:
B. Heating control circuit amperage draw
What can happen if defrost runoff is not properly drained away?
B. Ice can build up on the bottom of the coil
What is the typical method of staging a two stage compressor in a heat pump system?
B. It is based on deviation from the thermostat set point
The coefficient of performance (COP) of a heat pump is:
B. It's heat output in watts divided by its total electrical input in watts
On a service call for a cooling problem with the heat pump the inspection finds a liquid line that has condensation on it. What is the most likely cause?
B. Liquid line is restricted
The purpose of a sequencer in an auxiliary 20 KW electric heater is to energize:
B. One or two heating elements and the blower motor simultaneously, followed by remaining elements in timed intervals
When changing out an indoor coil the installer must be certain to:
B. Plumb the cabinet so it's sides are vertical
What three things happen when I heat pump is cycled into its defrost mode?
B. Reversing valve switches to the cooling mode, the outdoor fan is shut off and auxiliary heat is energized
In the heat pump power section of the schematic shown, what can be quickly determined about one of the components in the outdoor unit?
B. The defrost timer motor runs whenever L1 and L2 are powered
Why are there more circuits in a heat pump outdoor coil then in an AC condensing unit outdoor coil?
B. The pressure drop in the outdoor coil of a heat pump must be minimized
A wet bulb reading that is very close to the dry bulb reading from the same instrument indicates:
B. The relative humidity is very high
How should an indoor thermostat be set to perform and air balancing check of a cooling system?
B. The setting that brings on the medium high blower speed
What could cause a system evacuated to 500 µm to show an immediate and continuous rise in pressure when the vacuum pump is valved off?
B. There is a leak in the system
When wiring a 20 amp (FLA ) motor, The minimum circuit ampacity (MCA) should be:
C. 25 amps
In order for an evacuation to be considered complete, a heat pump refrigerant circuit should be evacuated to a minimum of:
C. 500 microns
In a low-voltage circuit, a corroded wire to terminal connection ask in the circuit like a:
C. Additional resistor
How does a technician check a compressor motor winding that is suspected of being grounded to the compressor housing(assume all power to the unit is off and the compressor wires have been removed from their terminals)
C. Check for continuity between the compressor terminals and ground with an ohmmeter
A high pressure limit control, used to shut down a compressor if condensing pressure becomes excessive, is typically installed to sense:
C. Compressor discharge line pressure
Refrigerant sub cooling is a measurement of the difference between:
C. Condensing saturation temperature and liquid line temperature
Heat pumps are typically sized for the conditions space based on the:
C. Cooling load
What is the effect of 170 V supplied to way 208/230 V compressor?
C. Current increases and the motor may trip on overload
A reason for cool air complaints when a heat pump is operating in the heat cycle is:
C. Excessive supply air velocities
When checking the pressures in an operating system with a manifold gauge set, refrigerant oil in a hose will:
C. Have no effect on the gauge reading
Undersized ductwork often cause:
C. High air quantities and high static pressures
According to fire protection codes when should fire dampers be used?
C. In any air duct that passes through all assemblies of a light commercial installation
What is the relationship between inrush current and holding current of a relay coil?
C. In rush current is always better than holding current
Where is the sensor of an outdoor ambient thermostat for a heat pump system typically installed?
C. In the entering airstream to the outdoor coil
Why does the outdoor fan on a heat pump stopped during defrost?
C. Minimize defrost time
What would cause a voltage reading across a closed contact in a 24 V control circuit?
C. Pitted or dirty contacts
What could cause a customer to complain that their single zoned home system in cooling mode feels sticky or damp?
C. Returns pulling in unconditioned air
What effect does a low charge have on the switch over operations of a reversing valve?
C. Reversing valves are less likely to shift if charge is very low
what is a primary consideration when bending soft copper tubing into a bed of any radius?
C. The cross-sectional area of the tube must not be significantly reduced
Reversing valves for heat pumps are typically manufactured with four refrigerant circuit tubes brazed to the body of the valve. One of the tubes is brazed to one side of the body and three tubes are brazed to the opposite side. To which part of the heat pump refrigerant circuit is the single tube connected?
C. The discharge line of the compressor
When performing maintenance on a heat pump the technician should check the outdoor fan to be certain:
C. The fan runs freely without binding or vibrations
The minimum circuit ampacity (MCA) listed on the data plate of a package to heat pump is used to determine:
C. The maximum fuse or a circuit breaker size
What is the thermal balance point of a dual fuel heat pump?
C. The outdoor conditions at which the capacity of auxiliary heat alone matches the heating load
When the load on a heat pump in the cooling mode decreases, suction pressure goes:
C. Up and discharge pressure goes down
A technician has determined a supply and a flexible duct system that has been pulled loose. How would this be repaired?
C. Using approved sealant and clamp
A disc type pressure switch which is located in a liquid line and opens on fall protects from?
C. loss of charge
The following measurements are recorded on an operating heat pump system. The heat pump is operating with the compressor only with no auxiliary heat. -heat pump only supply air temperature 92°F, heat pump only return air temperature 70°F, outdoor temperature 54°F, supply air temp./Auxiliary heat on 115°F, return air temp./Auxiliary heat on 70°F, CFM 1228 What is the heating capacity of the unit in BTU/H?
D. 29,177 btu/h
Electronica air cleaners can operate with internal voltages as high as:
D. 5000 V
With an R-410A condensing pressure of 395 psig and a liquid line temperature of 108°F what is the sub cooling temperature?
D. 8°F
What can cause a lower than normal suction pressure?
D. A restricted drier
Where should the technician check the voltage to an energized compressor?
D. At the load size of the compressor contactor
What is used to measure duct static pressure?
D. Differential pressure gauge
Two more accurately since the refrigerant temperature of horizontal suction lines that are one and an 8th inch or larger a thermostatic expansion valve sensing bulb that should be mounted at which positions?
D. Four or 8 o'clock
An electronica leak detector can typically detect a leak rate as small as?
D. Half an ounce per year
Suction line low pressure controls are often used in heat pumps to protect the compressor:
D. If suction pressure drops too low and to detect a loss of charge
What is one consideration when securing a refrigerant line set to reduce indoor operating sound?
D. Isolating refrigerant lines from direct contact with structure
Bent vanes on a direct Drive blower wheel in an air handler can cause:
D. Loss in airflow, excessive blower motor where, and increased noise
When selecting a high efficiency filter, which of the following criteria should be used to maintain proper airflow?
D. Maintain face velocity less than 100 ft./min.
Drive cleats are typically installed where on rectangular duct?
D. On the shorter sides
What is an effective method for reducing the sound transmissions from an air handler installed in a closet?
D. Place the cabinet on an isolation pad
A line voltage fuse is sized to:
D. Protect from excessive voltage
A residential supply diffuser that is noisy because of a loose vane is best serviced by:
D. Replacing the diffuser
When is vapor line condensation of a residential heat pump in the cooling mode a concern?
D. Routing refrigerant lines within wall
What kind of energy does the condenser remove from the refrigerant?
D. Sensible and Latent heat
What measurements are needed to determine low side superheat?
D. Suction pressure and suction line temperature
What measurements would be needed to properly evaluate a complaint of drafty operation with a heating system?
D. System TD, drop, and static pressure
The technician is using an analog multi meter to check a run capacitor. With the meter set to OHMS the needle swings towards zero and then slowly rise is toward infinity. What does this tell the technician about the capacitor?
D. The capacitor charges and discharges
Referred to the diagram above and answer the question: when troubleshooting and energized electrical circuit on an electric heat section, 244 V is measured across the element at points a and B and no amperage is measured. What is the problem with the system?
D. The electric element is open
A heat pump operates normally in first stage heating. The first and second stages appear to be calling, the single stage compressor continues to run, but the auxiliary electric heat does not come on. Which of the following should be included as a likely source of the problem?
D. The outdoor thermostat is closed
The following conditions exist in a circuit that supplies power to three parallel loads: One load is resistive, one load is capacitive, one load is inductive The total current in the circuit when operating will be:
D. The sum of the currents through each load
What effect would insufficient voltage or current have on a solenoid valve?
D. The valve will vibrate or chatter
What is the purpose of an auto change over system switch on a heat pump thermostat?
D. To automatically switch between heating and cooling as the load changes
According to manufacturers recommendations the most acceptable method for connecting a line set to an evaporator coil is:
D. Use only brazing alloys
In heating mode, a manifold gauge set is connected to the vapor and liquid line service valves of a properly charge system. What would the expected pressure be?
D. Vapor line will be higher and liquid line will be lower
Using a voltmeter, how does a technician determine voltage drop on the outdoor unit of a heat pump?
D. With the outdoor unit not operating and then with the outdoor unit operating
