Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

1: If the suction pressure is low and the evaporator temperature high, the cause will be a?

• starved evaporator
• too small evaporator
• compressor suction valve stuck open
• overcharged

2: The reversing valve is commonly used

• on commercial system that involve two different temperatures
• when the code requires a check valve
• on multiple compressor systems
• on all heat pumps

3: In an A/C unit, dirty filters will cause

• high discharge pressure
• low suction pressure
• low oil pressure
• high suction pressur

4: Cooling tower lowers condenser water temp by

• running water thru a secondary heat exchanger
• evaporative cooling
• condensation
• running fans at 100%

5: Ammonia systems use ____ pressure to adjust oil pressure

• liquid
• air
• stream
• discharge

6: The rupture disc on a low-pressure chiller typically releases pressure at

• 5 psig
• 0 psig
• 10 psig
• 15 psig

7: What is R-22?

• HFC
• Chlorofluoromethane
• CCFCM
• Chlorodifluoromethane

8: R-718 is rated unlimited for refrigeration quantity contained in a system. Why?

• Because it's a non-flammable refrigerant
• Because it's cheap
• Because it's water
• R-718 is not rated unlimited because it's a dangerous refrigerant

9: B3 refrigerants are considered

• non-toxic but non-flammable
• non-toxic but flammable
• toxic and highly flammable
• toxic but non-flammable

10: On a day with low relative humidity, the two thermometers on a sling psychrometer will read

• a ling psychrometer doesn't have two theremometers.
• far apart or greater difference
• nearly the same
• 2F difference

11: What refrigerant doesn't have to be classifted?

• R-134a
• R-718
• R-717
• R-711

12: 1 HP = ____ Watts?

• 11,239
• 3.1416
• 746
• 3,412

13: The critical temperature of a refrigerant gas occurs when

• any increase in pressure will not liquefy the gas
• the gas returns to a liquid
• the gas is no longer saturated
• any decrease in pressure will cause condensation

14: A normally operating R-410A system with a condensing temperature of 110F will have a high side pressure of around ______ psig

• 255 psig
• 125 psig
• 327 psig
• 365 psig

15: How many groups of refrigerants are there?

• 5
• 7
• 1
• 3

16: If your suction line is warmer than the room temperature, this may indicate

• a low charge
• plugged air filter
• below normal superheat
• an over charge

17: When testing systems using non-positive displacement compressors, the entire system shall be considered for test purposes as the low side.

• True
• False

18: What is absolute humidity?

• the amount of moisture in the air per one pound of 50% RH air
• the amount of moisture in the air in grains of cubic feet of volume
• the amount of moisture in the air in grains of square feet of volume
• none of the above

19: Direct systems using Group II refrigerants

• shall not be used for air condition for human comfort
• shall be installed per instruction of the AHJ
• shall be installed in Class T machinery rooms
• shall be allowed to be used for human comfort.

20: A chilled water pump suction gauge reads 10 psig. Discharge gauge reads 48 psig. The head in feet of the pump is working against

• 88
• 116
• 108
• 38

21: Evaporators located ____inches of a heating coil shall be equipped whit a pressure relief device.

• 15
• 24
• 10
• 18

22: When this is installed on the high side of a system, it must be capable of reading 1.2 times the design pressure (ASHRAE 15 9.11.3)

• Pressure gauge
• Temperature gauge
• Sight glass gauge
• All of the above

23: Watt's Law indicates Volts X Amps = _________.

• Watts
• Resistance
• Current
• Ohms

24: The 4 basic methods of determining whether the proper amount of refrigerant is being introduced into the system are

• Buss-eye, weight, pressure, and frost line
• sight glass, weight, pressure, and frost line
• sight glass, weight, pressure, and dipstick
• sight glass, weight, paper method, and frost line.

25: What is the maximum voltage range allowed on an electrical circuit?

• 15%
• 5%
• 20%
• 10%