Topics: All categories in the pool
1: Lithium-bromide, Li-Br, is best characterized as a
- sugar
- soil
- sand
- salt
2: The best way to detect ammonia in brine is
- CO2 gas
- potassium of line
- carbonation of soda
- nessler regaent
3: The purpose of a receiver is
- a vessel to store refrigerant outside the system
- to increase the capacity that the system can hold
- to use a a later date
- all of the above
4: A class A3 refrigerant is considered
- non-toxic and non-flammable
- toxic and non-flammable
- toxic and somewhat flammable
- non-toxic but highly flammable
5: Starting relays for a single phase compressors are used to remove the starting circuit from operation when the motor reaches approximately ____ percent of its speed.
- 50
- 75
- 24
- 100
6: Which refrigerant class listed below is the most flammable?
- B2
- A3
- A2
- C3
7: Which of the following controllers would you expect to be most sensitive to temperature changes?
- line voltage t-stat
- aquastat
- immersion controller
- low voltage t-stat
8: How many opening forces operate a thermostatic expansion valve?
- 1
- 2
- 3
- 4
9: Where can 50/50 solder be used on?
- suction line
- liquid line
- discharge line
- none of the above
10: Start to Run windings will have what resistance?
- The most resistance value
- All will be at equal values
- The least resistance value
- Somewhere between the actual start winding and run winding resistance value
11: What is not a requirement of a class T machine room?
- self-closing doors
- fire hose connection to the building fire protection system
- automatic ventilation
- tight fitting doors
12: When a refrigeration or air conditioning system is installed
- it shall not be operated below prescribed pressures
- the form of certificate shall be authorized by the Department of Pubic safety
- it shall be approved by the owner for proper operation.
- a field inspection shall be made before it is put into service
13: What are the three components of a transformer?
- Primary coil, secondary coil, and core
- Contacts, secondary coil, and core
- Primary core, secondary coil, and high and low voltage connectors.
- Primary coil, secondary coil, and copper contacts
14: Refrigerant systems containing Group I refrigerants can be installed in or on public stairways.
- True
- False
15: Total heat of a substance is considered
- sensible heat
- enthalpy
- specific heat
- empathetical
16: A line voltage thermostat controls a 1,200 watt strip header at 120 volts. What must be minimum ampere rated of the stat be?
- 10 amps
- 15 amps
- 20 amps
- 5 amps
17: Methyl Chloride is a halogenated refrigerant and should not come in contact with
- aluminum
- zinc
- magnesium
- all of the above
18: The level of voltage caused by back electromagnetic force that opens the contacts of a potential relay in order to take the start capacitor out of the circuit is
- boost voltage
- lift voltage
- pick up voltage
- run voltage
19: Pressure is equivalent of
- Force / Area
- Force X Area
- Force
- Area X Force
20: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 4%
- 25%
- 1%
- 2%
21: The freezing point of water at sea level is?
- 32C
- 0F
- -10C
- 32F
22: An evaporator coil located near heating coil shall have a pressure-relief device installed within ______ inches of the evaporator.
- 24
- 36
- 48
- 18
23: 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
24: How far from the ground does a relief valve need to be?
- At least 15' above grade
- At least 20' above grade
- At least 25' above grade
- Not more than 3' above grade
25: Calculate the voltage in a series circuit when the total amperage is 10 amps and the resistors have values of: R1=12 ohms, R2=8 ohms, R3=4 ohms
- 240 volts
- 24.0 volts
- 2,400 volts
- 2.40 volts