To safely increase the pressure in a refrigerant cylinder while charging a system, the technician should:
A) Run warm water over the cylinder.
B) Heat the top of the cylinder with a small propane torch.
C) Heat the bottom of the cylinder with a small propane torch.
D) Immerse the cylinder in a tub of boiling water.
[Ques. 2] What do air-quality sensors measure?
A) Temperature, velocity, and pressure B) CO2, enthalpy, and humidity
C) Ozone and NOx levels D) O2 and NOx levels
[Ques. 3] Because air-source heat pumps circulate less refrigerant at low ambient temperatures, the refrigerant not being used is stored:
A) In the metering device.
B) In a liquid receiver.
C) In a suction accumulator or charge compensator.
D) In the compressor crankcase.
[Ques. 4] What would the mixed air temperature be for a system with 20 outdoor air if the outdoor temperature is 90F and the return air temperature is 80F?
A) 0.8 90F =18F; 18F + 80F = 98F mixed air temperature
B) (90F + 80F) 0.4 = 68F
C) 0.2 90F =18F; 0.8 80F = 64F; 18F + 64F = 82F mixed air temperature
D) (90F + 80F)/2 = 85F mixed air temperature
[Ques. 5] Hot Surface Ignition System (HSI) controls lockout after how many unsuccessful attempts?
A) Two attempts B) The controls do not lock out.
C) Three or more attempts D) One attempt
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