Topics: All categories in the pool
1: Relief valves are rated in
- pounds of air per hour
- pounds of air per minute
- gallons of water per hour
- gallons of water per minute
2: Methyl Chloride is a halogenated refrigerant and should not come in contact with
- aluminum
- zinc
- magnesium
- all of the above
3: The dial of a pressure gauge, when installed on the high side of a system be graduated 1.2 times the designed pressure.
- True
- False
4: Sublimation occurs when
- gas is formed from a liquid
- ice melts and turns to water
- gas is formed directly from a solid
- liquid is formed from a gas
5: When an electronic bridge is in balance the bridge output will be
- 1 volt
- 15 volts
- .01 volts
- 0 volts
6: When energized, a normally open relay will be
- noisy
- depends on the type and class of the relay
- closed
- open
7: What is not a requirement of a Class T machine room?
- Tight fitting doors
- Fire hose connected to the building fire protection system.
- Automatic ventilation
- Self-closing doors
8: A chilled water pump's suction gauge reads 10 psig. The discharge gauge reads 48 psig. What is the head in feet the pump is working against?
- 58
- 96
- 38
- 88
9: Indirect systems using Group II refrigerants
- shall be used in refrigeration system less than 1,000 lbs
- shall be used in refrigeration system in excess of 1,000 lbs
- shall have all refrigerant containing parts except piping, installed in a Class T machine room
- shall be used for mechanical equipment only
10: The critical temperature of a refrigerant gas occurs when
- any increase in pressure will not liquefy the gas
- the gas is no longer saturated
- the gas returns to a liquid
- any decrease in pressure will cause condensation
11: The 522 CMR 9.00 has adopted for reference ASHRAE ____
- 10
- 15
- III
- 25
12: What is the minimum size of the discharge pipe?
- Same size as the outlet of the relief valve
- One pipe size larger that the inlet of the relief valve
- Depends on size of manifold
- All of the above
13: What is the boiling point of refrigerant governed by?
- P&T relationship
- Condenser sub-cooling
- Compressor RPM's
- Evaporator temperature
14: Refrigerant restricted in 2004 but used for transition for decades:
- R-11
- R-123
- R-22
- R-134A
15: One watt of electrical energy in a resistive heater will provide _____ BTU/hr
- 6.830
- 3.415
- 34.15
- 16.64
16: The normal operating evaporator temperature of R-410A for air conditioning is typically
- 32F
- 158F
- 155F
- 45F
17: Fractionation occurs when
- the pressures decreases as the heat load decreases
- the pressures increase as the heat load increases
- some of the blended refrigerant evaporates or condenses before the rest of the blend
- when a fraction of refrigerant is added as the full charge
18: Pressure vessels with an internal volume of 3 cubic feet or less
- shall use pressure relief devices
- do not need pressure relief protection
- shall use fusible plugs
- shall use pressure relief devices or fusible plugs
19: The absorber shell contains the
- condenser, the evaporator, and the generator
- evaporator and the absorber
- condenser and the absorber
- condenser and the generator
20: While the system is operating, the discharge line should be
- at the same temperature as the crankcase
- 10-15F warmer than ambient
- too hot to hold by hand
- room temperature
21: Which oil is hydoscopic?
- mineral
- animal
- SW30
- polyolester
22: Where must a refrigeration contractor's license number be displayed?
- Truck, office, every job, and on all equipment
- Uniforms, checks, and invoices.
- Trucks, license plates, and uniforms
- Trucks, invoices, and advertising
23: An electronic bridge circuit is basically a
- Wheatstone
- high voltage circuit
- suspension
- 24 volt control circuit
24: How do you find net oil pressure on a compressor?
- discharge pressure - suction pressure
- gross oil pressure - suction pressure
- gross oil pressure - discharge pressure
- all of the above
25: What type of fuses must be used on a HVAC system?
- TR Type, Duel Element, Time Delay
- Fast blow
- 10% lower than RLA
- none of the above