Topics: All categories in the pool
1: The main purpose of the accumulator is to
- store liquid refrigerant
- provide space for vapor to accumulate
- prevent liquid slugs at the compressor
- provide space for the accumulation of oil and containminants
2: The critical temperature of a refrigerant gas occurs when
- any decrease in pressure will cause condensation
- the gas is no longer saturated
- any increase in pressure will not liquefy the gas
- the gas returns to a liquid
3: A hissing noise at the expansion valve is a good indication that
- expansion valve is oversized
- liquid is passing thru it
- gas is passing thru it
- nothing is passing thru
4: Name a CFC refrigerant(s):
- R-11
- R-12
- R-123
- both a & b
5: R-410A is classified as a ____ refrigerant on the safety matrix.
- A-1
- B-2
- B-1
- A-2
6: What type of relief valve is used on low pressure centrifugal compressor systems?
- Spring-loaded relief valve
- Rupture disc
- Purge relief
- None of the above
7: What should not (and can not) be located between a pressure imposing device and a pressure-limiting device?
- Stop valve
- Moisture indicator
- Muffler
- Foot valve
8: When is the space above a drop ceiling calculated as space for refrigerant limit quantities?
- When its white
- When there are sprinklers above
- When there is a space 6' or more above it
- When it's used as part of a supply or return air system
9: What type refrigerant is NOT ozone depleting?
- HCFC
- HFC
- Halon
- CFC
10: What is the purpose of suction/discharge traps?
- to ensure proper oil return to the compressor
- to keep oil inside the evaporator for proper oil return to the compressor
- to keep oil inside of the accumulator for proper return to the compressor
- all of the above
11: NH3 is
- R-508A
- lithium bromide
- R-718
- ammonia
12: A high side float is a
- float type valve that controls the amount of refrigerant stored in the receiver
- metering device used on critically charged systems that controls the level of the liquid refrigerant in the high pressure side of the system.
- float type switch that stops the compressor when the pressure on the high side becomes too high
- float type valve that controls the crankcase oil level
13: Where can 50/50 solder be used on?
- suction line
- liquid line
- discharge line
- none of the above
14: A water regulating valve opens when
- the compressor is on
- when the power is on there is an overcharge of refrigerant
- the head pressure rises
- when the power is on
15: Excessive head pressure is often caused by
- thermostat set too high
- air cooled condenser is plugged
- leaking reed valve on the discharge side
- insufficient refrigerant
16: How far from the ground does a relief valve need to be?
- At least 15' above grade
- At least 20' above grade
- Not more than 3' above grade
- At least 25' above grade
17: A 50 VA control transformer with a 25 volt control output would be rated for _________ amps.
- 2.5
- There isn't enough information to answer.
- 1250
- 2
18: The rupture disc on a low-pressure chiller typically releases pressure at
- 0 psig
- 5 psig
- 15 psig
- 10 psig
19: What type of voltage causes the winding in a potential relay to open?
- BEMF (Back Electro-Motive Force)
- 24V control voltage from the thermostat
- 120V line voltage
- None of the above
20: It takes how many BTU/hr to melt one pound of ice at 32F
- 970
- 180
- 144
- 212
21: Suction valve unloaders afford an effective means of
- evaporator control
- superheat control
- refrigerant control
- capacity control
22: What kind of system uses two different refrigerants in separate systems dependent on each other?
- Cascade
- Low pressure
- Simple
- R-414B
23: What will occur if the strong solution in an absorption chiller becomes too strong?
- The machine will stop cooling and solution will crystallize
- The machine will stop cooling and the solution will evaporate.
- The machine will cool excessively as the solution evaporates
- The machine will cool excessively as the solution crystallizes.
24: There can be no airflow from an occupied space through a machine room unless what?
- System is high velocity
- System is ducted and sealed
- Duct is not located in the ceiling
- None of the above.
25: Which creates more of a heat load?
- 70% RH
- 30% RH
- 90% RH
- 50% RH