Topics: All categories in the pool
1: Which of the following types of oils are hygroscopic?
- polyolester (POE)
- polyalkylene glycol (PAG)
- naphthene mineral
- both a and b
2: A secondary coolant is defined as
- any refrigerant direcly in contact with the cooling space for process cooling
- a low temperature refrigerant used for cascading systems
- a combination of interconnected parts from a closed circuit in where fluid is circulated for the purpose of cooling for a refrigeration system.
- any liquid used for the transmission of heat without a change of state in A/C refrigeration systems having flash point above 150F
3: Where is the high-side float located on a chiller system?
- flash line
- liquid line
- inside the chiller barrel
- discharge line
4: The actual expansion curve of compression follows most nearly which one of the following curves?
- Isothermal
- Adiabatic
- Volume Temperature
- Pressure Temperature
5: Atmospheric pressure is equal to
- 29.92" Hg
- 14.7 psia
- 14.7 psig
- both a & b
6: What do you need to do when you install a new system?
- Add refrigerant
- Have it inspected
- Insulate the suction line before you take a superheat reading
- Document the superheat and subcooling reading
7: How many gallons of water per pound of ammonia do you need?
- 1
- 5
- 20
- 15
8: R-11 has the greatest corrosive effect on
- Magnesium
- Aluminum
- Copper
- Bronze
9: If a refrigerant leaving the condenser is 94F and the condensing temperature is 105F, the subcooling is
- 21F
- 11F
- 9F
- 29F
10: What instrument is used to measure very high resistance?
- tape measure
- ammeter
- meg ohmmeter
- voltmeter
11: When an A/C system is excessively low on refrigerant
- it can become contaminated with water
- there can be nuisance trip outs
- the suction line may be too hot to touch
- All of the above
12: A run capacitor is wired in series with the _____ windings.
- common
- run
- start capacitor
- start
13: On an air cooled condenser, if the ambient air is 35F and dropping, what's its effect to the condensor?
- it would have no effect on the condenser
- it would make the condenser less efficient
- it would make the condenser more efficient
- it would cause the condenser to sweat
14: Heat that changes the physical state of a substance without effecting a change in its temperature is known as
- latent heat
- specific heat
- lost heat
- sensible heat
15: On cooling towers, what causes the condenser water to drop
- ambient temperatures
- tower fans
- sensible heat
- evaporation of the water droplets
16: Refrigeration piping before being buried shall be
- leak tested
- encased in pipe duct
- pressure tested
- All of the above
17: In a motor, an internal overload might open if
- there's an excess current draw through the motor
- there was a high pressure refrigerant was used for a low pressure system.
- there's a direct short
- there's an open start winding
18: Liquid level gauge glasses shall have automatic closing shut off valves, except Bull's eye or reflex type.
- True
- False
19: Transformers are rated in
- volts
- volts-ohms
- amps
- volt-amps
20: What refrigerant has zero ozone depletion
- HFC
- CFC
- HCFC
- None of the above
21: The Board of Boilers adopts by reference
- MSCA Code
- the 1997 ANSI/ASHRAE Safety Code
- the MACS Pressure Vessel Code of Massachusetts
- Montreal Protocol Safety Code
22: What does an anemometer measure?
- velocity
- temperature
- voltage
- amperage
23: Bubbles in the liquid line sight glass could be caused by
- bad low pressure switch
- overcharge of oil
- leaking discharge valves in the compressor
- plugged drier
24: When can 50/50 solder be used?
- in the low side
- in the high side
- liquid and suction lines
- none of the above.
25: In a refrigeration system, you open a valve from the condenser and collect some material on a clean white sheet of bond paper, which of the following would you most likely be testing for?
- checking the level of refrigerant in the system
- testing for oil in the system
- testing for moisture in the system
- none of the above