Topics: All categories in the pool
1: Before you change the type of refrigerant in a refrigeration system, what three things must be done?
- place sign, check for leaks, insulate
- nothing must be done
- make sure it's compatible, notify owner, notify A.H.J
- you can't change refrigerants
2: In designing duct work, pressure and ______ need to be considered
- length
- CFM
- duct sealant used
- all of the above
3: Excessive head pressure is often caused by
- leaking reed valve on the discharge side
- thermostat set too high
- insufficient refrigerant
- air cooled condenser is plugged
4: A declaration test is needed when the system contains more than
- 110 lbs
- 65 lbs
- 120 lbs
- 55 lbs
5: "P" represents ______ in the Watt's law formula
- amperage
- watts
- voltage
- reactance
6: A pressure relief should be located at least _______ from windows and doors.
- 30'
- 20'
- 25'
- 15'
7: A tachometer is an instrument used to measure
- speed
- static pressure
- air velocity
- RPM
8: What is not a requirement of a class T machine room?
- automatic ventilation
- self-closing doors
- fire hose connection to the building fire protection system
- tight fitting doors
9: A pressure-limiting device isn't required on a factory-sealed system containing less than ____ lbs.
- 50
- 22
- 25
- 66
10: What type of fuses must be used on a HVAC system?
- TR Type, Duel Element, Time Delay
- Fast blow
- 10% lower than RLA
- none of the above
11: A Category D fluid
- is when the fluid handled is non flammable, nontoxic, and not damaging to human as defined in ANSI/ASME Process Piping.
- is when the design pressure does not exceed 150 psi
- a fluid for service piping in which the potential for personnel exposure is judged to cause harm and irreversible damage to those persons exposed to it
- Both a and b are correct
12: Single compound Refrigerants are classified by what two criteria?
- Flammability and temperature range
- Flammability and toxicity
- Weight and color
- Temperature range and hazardousness
13: A 24 volt transformer with a 240 volt primary can handle how many amps?
- 24 amps
- 10 amps
- There isn't enough information to answer.
- 20 amps
14: What is a Category "M" fluid?
- Any fluid that exceeds 150 psig and has design temperatures over 366F
- A toxic fluid, which can produce serious irreversible harm to persons on breathing or bodily content
- A typical refrigerant used on newer air conditioning and heat pump systems
- A fluid which is nonflammable, nontoxic, not damaging to human tissues, does not exceed 150 psig, and the designed temperature is between -20F to 366F
15: 1 HP = ____ Watts?
- 11,239
- 746
- 3.1416
- 3,412
16: What is Trichlorotrifluoromethane?
- R-13
- R-113
- R-11
- R-12
17: How do you find net oil pressure on a compressor?
- discharge pressure - suction pressure
- gross oil pressure - suction pressure
- gross oil pressure - discharge pressure
- all of the above
18: 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
- 2,400 volts
- 2.40 volts
- 24.0 volts
19: A VRF system is a direct system
- true
- false
20: When is the only time you can leave a service container attached to a system?
- Leaking system
- Recovery
- Charging
- Both b and c
21: _____ and its alloys are suitable for use with ammonia systems.
- Copper
- Zinc
- Magnesium
- Aluminum
22: 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
23: A pressure vessel having an inside diameter of 6” or less shall be sufficient to withstand ____times the pressure of the saturation temperature of the refrigerant or ____times the critical pressure of the refrigerant, whichever is less.
- 2.5, 2.5
- 6.6, 6.6
- 3.0, 3.5
- 2.5, 3.0
24: When a receiver is greater than 3 cubic feet but less than 10 cubic feed, what is the minimum relief device required?
- fusible plug
- relief valve
- rupture disc
- all of the above
25: Two capacitors are wired in parallel. One capacitor has a value of 15uf. The other has a value of 25uf. What is the total value supplied?
- 40 uf
- 15 uf
- 20 uf
- 25 uf