Topics: All categories in the pool
1: A line voltage thermostat controls a 1,200 watt strip header at 120 volts. What must be minimum ampere rated of the stat be?
- 20 amps
- 10 amps
- 15 amps
- 5 amps
2: "E" represents _____ in the Watt's law formula.
- voltage
- watts
- reactance
- amperage
3: Ammonia (NH3) is a group III refrigerant
- True
- False
4: A EPR valve is installed on what type of evaporators?
- low-temperature evaporators
- shell and tube evaporators
- high-temperature evaporators
- plate evaporators
5: High side floats are used on centrifugal chiller systems are are considered critically charged systems.
- are obsolete.
- True
- depends on the type of refrigerant being used
- False
6: What is the refrigerant dichlorodifluoromethane?
- R-22
- R-134A
- R-123
- R-12
7: A capacitor in series with the start windings will do what?
- Increase starting torque
- Nothing
- Decrease the RLA to within 10% of its rating
- Increase run efficiency by 10% of its rating
8: The amount of heat required to raise the temperature of 1 lb of water 1F is?
- The rate of conduction
- 1 Kelvin
- 1 Therm
- 1 BTU
9: The total amount of refrigerant stored in a machinery room in all containers not provided with relief valves shall not exceed
- 330 lbs.
- 660 lbs
- 550 lbs
- 55 lbs
10: What must be done to refrigerant pipes before being buried?
- Encased
- Coated
- Leaked checked
- Certified
11: The freezing point of water at sea level is?
- 32C
- 32F
- 0F
- -10C
12: Ammonia systems use ____ pressure to adjust oil pressure
- liquid
- discharge
- stream
- air
13: What effect does the temperature of air have on humidity?
- warmer air holds more moisture then cooler air
- cooler air holds more moisture then warmer air
- air has no effect of humidity
- none of the above
14: A compressor in which the increase in vapor pressure is attained without changing the internal volume of the compression chamber is called
- negative displacement compressor
- non-volumetric displacement compressor
- neutral chamber-type compressor
- non-positive displacement compressor
15: R-22 falls under which safety classification?
- A-2
- B-2
- A-1
- B-1
16: Capacity control on a centrifugal compressor is accomplished by the
- slide vanes
- post-rotational guide vanes
- check valves
- pre-rotational guide vanes
17: Which refrigerant was still able to be vented to the atmosphere after July 1, 1992?
- R-22
- R-113
- R-12
- R-11
18: A high side float is a
- float type switch that stops the compressor when the pressure on the high side becomes too high
- float type valve that controls the amount of refrigerant stored in the receiver
- float type valve that controls the crankcase oil level
- metering device used on critically charged systems that controls the level of the liquid refrigerant in the high pressure side of the system.
19: Class 3 refrigerants are
- toxic
- non-toxic
- non-flammable
- highly flammable
20: 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
21: Laten heat is associated with a change in state of a refrigerant but not temperature
- True
- False
22: How are refrigerant blends classified?
- Based on the oil used
- Based on worst case fractionation
- Blends don't have to be classified
- Based on best case Fractionation
23: Defined process piping by code CMR (528)
- Any piping that conveys a solid, liquid or gas that is not part of the plumbing or fire protection system
- Any piping in an industrial space
- Any piping in an industrial or commercial space
- All of the above
24: When liquid receivers are used, the liquid refrigerant shall not exceed _______percent of the volume at 90F.
- 99%
- 80%
- 75%
- 90%
25: Where would the EPR valve be located on a multiple evaporator system?
- outlet of high temperature evaporator
- inlet of the low temperature evaporator.
- outlet of low temperature evaporator
- outlet of the liquid line