Topics: All categories in the pool
1: What refrigerant doesn't have to be classified?
- R-717
- R-422A
- R-134A
- R-718
2: What must be done to refrigerant pipes before being buried ?(8.10.4)
- Leak checked
- Insulated and installed in a pipe duct (Encased)
- Classifed
- Certified
3: When should a relief valve start to function?
- Two times it's working pressure
- Before the purge station discharges
- At it's set pressure
- 10 psi before it's set pressure
4: A self contained system
- is any system or part of a system used to increase evaporation by expansion or vaporization
- is a unit system Group I refrigerants only
- is a complete factory made and tested system
- is a unit system Group II refrigerants only
5: What's the purpose of a megohmmeter?
- To measure low to very low resistance values
- To alternate the current in a DC circuit in order to calculate the total impedance of a circuit
- To measure very high resistances
- None of the above
6: When is the only time you can leave a service container attached to a system?
- Leaking system
- Recovery
- Charging
- Both b and c
7: 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
8: High pressure controls should be set no higher than
- 80% of set point
- 10% of set point
- 25% of set point
- 90% of set point
9: 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
10: On cooling towers, what causes the condenser water to drop
- sensible heat
- tower fans
- evaporation of the water droplets
- ambient temperatures
11: Clearance volume
- has no effect on compressor capacity
- is the same on all compressors
- affects compressor capacity
- varies depending on compressor speed
12: Ammonia can come in contact with _______ ?
- Copper
- Aluminum
- Brass
- Copper tubing
13: Pressure limiting devices are not required for systems containing less then ________ refrigerants.
- 6.6 lbs
- 13.9 lbs
- 22 lbs
- 44 lbs
14: Class A refrigerants are considered
- toxic
- flammable
- non-flammable
- non-toxic
15: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?
- Nesting scrolls
- Fan-like action
- Rotating vanes
- Suction and discharge valves
16: The certificate of inspection
- shall be $20 and an additional fee of $1 for each tone above 20 tons
- shall be posted on the compressor shell or electrical panel at the unit
- shall be authorized by a notarized insurance company
- shall be posted and protected from dirt, water, and other elements
17: What instrument is used to measure very high resistance?
- voltmeter
- tape measure
- meg ohmmeter
- ammeter
18: Megaohm meter's main function is
- to detect weak motor winding insulation of a refrigeration or air conditioning compressor by creating high DC voltages to the compressor
- to detect very high resistances to ground of refrigeration or air conditioning compressors
- to test very high value capacitors for large 3-phase refrigeration compressors and blower motors.
- Both a and b are correct
19: Low temperature systems should have what?
- High pour point
- Low pour point
- High viscosity
- None of the above
20: Oils, classified as to source, are
- animal, vegetable, and castor
- naphthalene, paraffin, and castor
- animal, vegetable, and mineral
- naphthalene, mixed, and paraffin
21: The solution that is pumped into the concentrator in an absorption chiller is referred to as the
- absorbed solution
- weak solution
- strong solution
- concentrated solution
22: A R-22 system running with a condensing temperature of 110F and a 40F evaporator temperature will read pressures of ____ on the high side and ____ on the low side.
- 455 psig, 185 psig
- 257 psig, 77 psig
- 350 psig, 120 psig
- 226 psig, 68 psig
23: Where can 50/50 solder be used on?
- suction line
- liquid line
- discharge line
- none of the above
24: If the suction pressure is low and the evaporator temperature high, the cause will be a?
- compressor suction valve stuck open
- overcharged
- starved evaporator
- too small evaporator
25: Which refrigerant class listed below is the most flammable?
- B-2
- A-1
- A-3
- C-3