Topics: All categories in the pool
1: When should a relief valve start to function?
- Before the purge station discharges
- 10 psi before it's set pressure
- Two times it's working pressure
- At it's set pressure
2: _____ alloys shall not be used in contact with an halogenated refrigerants.
- Magnesium
- Zinc
- Copper
- Nickel
3: The most common type of motor starter is
- delts-wye starter
- duel-winding starter
- across the line starter
- part winding starter
4: While water is evaporated in an evaporative condenser the impurities which were in the water are
- blown to the atmosphere by the fan
- washed out of the air by the spray pump
- remain in the air
- accumulate in the sump water
5: A normally operating R-410A system with a condensing temperature of 110F will have a high side pressure of around ______ psig
- 255 psig
- 125 psig
- 327 psig
- 365 psig
6: "E" represents _____ in the Watt's law formula.
- reactance
- amperage
- watts
- voltage
7: Direct systems using Group II refrigerants
- shall not be used for air condition for human comfort
- shall be installed per instruction of the AHJ
- shall be installed in Class T machinery rooms
- shall be allowed to be used for human comfort.
8: Secondary refrigerants are usually
- alcohol
- Prestone anti-freeze
- expensive
- water or brine
9: In an air conditioning system, the unit of total heat energy content in an air/vapor mixture is
- Sensible heat
- Enthalpy
- Latent heat
- Specific heat
10: How many gallons of water do you need per pound of ammonia?
- 100
- 1
- 10
- 50
11: A halide torch is most useful with a freon compression system
- to sweat flanges on the refrigeration piping
- to remove from from TXV's and evaporator coils
- to release a sticking valve
- to detect refrigeration leaks in piping joints
12: Capacitors are rated in
- volt - amperes
- kelvins
- micro-farads
- megaohms
13: Volts x amps equals
- Ohms Law
- Watts
- Inductance
- Impedance
14: The purpose of an accumulator is to
- assure no liquid returns to the compressor
- filter out impurities from the system
- reduce friction loss to the flow of refrigerant
- store excess refrigerant from the reciver
15: Which refrigerant class listed below is the most flammable?
- B-2
- A-3
- A-1
- C-3
16: Which refrigerant was still able to be vented to the atmosphere after July 1, 1992?
- R-11
- R-22
- R-12
- R-113
17: Capacity control on a centrifugal compressor is accomplished by the
- post-rotational guide vanes
- check valves
- slide vanes
- pre-rotational guide vanes
18: 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
19: A positive displacement compressor is
- a compressor in which the increase in pressure is attained by changing the internal pressure of the compression chamber
- where the compressor's suction pressure and the compressor;s discharge pressure is more than 50 PSI
- a compressor in which the increase in pressure is attained by changing the internal volume of the compression chamber
- is a reciprocating type compressor with 2 or more pistons
20: A start capacitor in series with a start winding will
- increase starting torque
- decrease the amp draw of the motor
- increase running efficiency
- increase the amp draw of the motor
21: The actual expansion curve of compressor follows most nearly which one of the following
- Adiabatic
- Pressure-Temperature
- Isothermal
- Volume
22: In an air conditioning plant which an indirect low side, water is used inside of bring: the proper sequence of operating the plan is
- reset the expansion valve
- start the comrpessor
- start the fan and circulating pump
- reset the safety valve
23: Low ambient controls are used when
- on air conditioning systems only
- economizers are used
- when systems run all year round
- always
24: What type of relief valve is used on low pressure centrifugal compressor systems?
- Spring-loaded relief valve
- Rupture disc
- Purge relief
- None of the above
25: Cooling tower lowers condenser water temp by
- evaporative cooling
- running water thru a secondary heat exchanger
- running fans at 100%
- condensation