Topics: All categories in the pool
1: Liquid line filter-driers on a 410A system must be rated for no less than
- 600 psig
- 1000 psig
- 400 psig
- 200 psig
2: Insurance companies shall forward each inspection report of all refrigeration or A/C systems to the Chief of Inspections within
- 1 week
- 30 days
- 14 days
- 2 months
3: All electrical work done on refrigeration systems must comply with
- Department of Energy
- NEC and Massachusetts Modifications
- ASHREA-15 Section 9.2.1
- OSHA
4: 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
5: What is the voltage of each leg to ground of a three-phase motor with a 460v supply voltage?
- 240v
- 120v
- 208v
- 277v
6: Which creates more of a heat load?
- 30% RH
- 70% RH
- 50% RH
- 90% RH
7: Materials used in construction and installation materials used in the manufacture or installation of refrigerating equipment shall be suitable for conveying refrigerant and the refrigerant oils and will not deteriorate in the presence of what?
- Moisture and air
- Water and soap
- Oil and water
- Air and dirt
8: Pressure is the equivalent of
- force times area
- force
- force per unit area
- area times force
9: What should never be used in pressure testing refrigeration systems?
- Oxygen
- Compressed air
- Nitrogen
- Both a and b
10: Ammonia systems use ____ pressure to adjust oil pressure
- discharge
- liquid
- stream
- air
11: Pairs of mating stop valves that allow sections of a system to be joined before opening these valves or separated after closing them are
- ball valves
- companion or block valves
- king valves
- gate or globe valves
12: 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
13: How many BTU's is produced by one watt of energy
- 1
- 2.57
- 3.00
- 3.41
14: Who is permitted to access a refrigeration machine room?
- Any employee
- Authorized persons only
- Anyone, it's a completely safe area
- Contractors only
15: Which is considered the more efficient condenser?
- water cooled
- spray cooled
- fan cooled
- air cooled
16: Before determining if a machinery room equipment is excluded from following Ashrae 15, you must determine how many pounds of refrigerant per _____ cubic feet?
- 1,000
- 100
- 100,000
- 10,000
17: Halogen refrigerants are corrosive to which type of metal?
- copper
- magnesium
- black iron
- stainless steel
18: How many gallons of water do you need per pound of ammonia?
- 100
- 50
- 1
- 10
19: An oil pressure safety switch should be set at
- 5 to 10 psi below low side pressure
- 5 to 10 psi above low side pressure
- 10 to 15 psi below low side pressure
- 10-15 psi above low side pressure
20: Pressure limiting devices are not required for systems containing less then ________ refrigerants.
- 6.6 lbs
- 13.9 lbs
- 22 lbs
- 44 lbs
21: Capacity control on a centrifugal compressor is accomplished by the
- slide vanes
- post-rotational guide vanes
- check valves
- pre-rotational guide vanes
22: Pressure vessels of 10 cubic feet or more gross volume shall use
- at least one rupture member
- a dual pressure-relief valve if charging into the atmosphere
- at least three means of discharge and/or rupture discs
- both a and b are correct
23: If a refrigerant leaving the condenser is 94F and the condensing temperature is 105F, the subcooling is
- 9F
- 11F
- 21F
- 29F
24: What is the voltage of each leg of a 480 Volt three-phase motor?
- 208v
- 240v
- 277v
- 120v
25: What is potential measured in?
- Ohms
- Volts
- Amps
- Henrys