A suction line accumulator should be used in a residential heating pump only when recommended by the manufacturer if:
a. Long refrigerant lines increase system charge over recommended maximum charge
b. added oil dilution is required to maintain proper lubrication
c. the system has low vap...
NATE Practice Exam CORRECT 100%
A suction line accumulator should be used in a residential heating pump only when recommended by
the manufacturer if:
a. Long refrigerant lines increase system charge over recommended maximum charge
b. added oil dilution is required to maintain proper lubrication
c. the system has low vapor line pressure drop and accumulator is added to improve efficiency
d. the system does not include a high pressure switch or time delay - ANSWERA. Long refrigerant
lines increase system charge over recommended maximum charge
What three things happen when a heat pump is cycled into its defrost mode?
a. reversing valve switches to the heating mode, and the outdoor fan is shut off and auxiliary heat is
energized
b. reversing valve switches to the cooling
mode, crankcase heat is de-energized and
auxiliary heat is energized
c. reversing valves switches to the cooling mode, the outdoor fan is shut off and auxiliary heat is
energized
d.reversing valves switches to the heating mode, the outdoor fan is shut off and auxiliary heat is de-
energized - ANSWERc. reversing valves switches to the cooling mode, the outdoor fan is shut off and
auxiliary heat is energized
Which of the following is a benefit in using an electronic air cleaner?
a. the ozone level is decreased
,b. all odors are removed
c. the air cleaner will not require cleaning
d. indoor air quality (IAQ) is improved - ANSWERd. indoor air quality (IAQ) is improved
A technician has the following conditions while checking a packaged heat pump in cooling.
*The unit has a piston type metering device on both the indoor and outdoor coils
*Outdoor temperature 75 degrees F
*Superheat 55 degrees F
What is the diagnosis and corrective action?
a. the unit is low on charge refrigerant needs to be added
b. the unit is operating properly and no further repair is needed
c. the unit is overcharged and charge needs to be recovered
d. there is a problem with airflow over the indoor coil and the filter needs to be changed or the
blower repaired - ANSWERa. the unit is low on charge refrigerant needs to be added
A Capacitor Start-Capacitor Run ( CSCR) motor has an open run capacitor. Will it start?
a. It may start, but it draws a higher than normal running current.
b. No, it would be unable to start without the run capacitor.
c. It can only start if the voltage is higher.
d. Yes, it will start, but it will run backwards. - ANSWERa. It may start, but it draws a higher than
normal running current.
,Why does the outdoor fan on a heat pump stop during defrost? - ANSWERa. minimize defrost time
b. decrease high side pressure
c. reduce compressor noise
d. increase defrost time
A heat pump operates normally in first stage heating. The first and second stage bulb appear to be
calling
compressor continues to run, but the auxiliary electric heat does not come on. Which of the
following
be included as a likely source of the problem?
a. the indoor blower is defective
b. the second stage heating circuit is open
c. the outdoor thermostat is closed
d. the thermostat anticipator is out of adjustment - ANSWERb. the second stage heating circuit is
open
What effect would insufficient voltage or current have on a solenoid valve?
a. the valve will remain half open
b. the valve will vibrate or chatter
c. it causes flash gas formation
, d. the valve will operate normally - ANSWERb. the valve will vibrate or chatter
Why is operating sound a consideration in the location of a condensing unit?
a. sound levels and system efficiency are closely related
b. excessive noise could be disruptive to the customer
c. condensing the unit sound is amplified by shrubbery
d. condensing sound is eliminated by shrubbery - ANSWERb. excessive noise could be disruptive to
the customer
With R-22 condensing pressure of 246 psig and a liquid line temperature of 108 degrees F what is the
sub-cooling?
a. 24 degrees F
b. 8 degrees F
c. 36 degrees F
d. 16 degrees F - ANSWERb. 8 degrees F
When using a double (dual) element time-delay fuse with a 20 amp motor, the maximum fuse size
should be:
a. 20 amps
b. 60 amps
c. 30 amps
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