Liquid floodback commonly occurs on air-source heat pumps:
A) When the defrost cycle is terminated and the cycle reverses.
B) When the heat pump is operated in cooling with a low charge.
C) When the liquid filter drier is stopped up.
D) When the heat pump is operated in heating on a warm day.
[Ques. 2] When is the igniter energized on an induced draft furnace that uses hot surface ignition?
A) At the same time the induced draft blower is energized
B) After the draft switch closes to prove the draft
C) At the same time the gas valve is energized
D) On the initial call for heat
[Ques. 3] Industry associations that establish national standards for the HVACR industry include:
A) ARI, ASHRAE, and UL.
B) AC Standards Association and the Heating Standards Symposium.
C) DOT, MSHA, and CE.
D) EPA, OSHA, and DOE.
[Ques. 4] Variable refrigerant flow systems use:
A) Inverter driven systems and electronic expansion valves.
B) Inverter driven systems and thermostatic expansion valves.
C) Scroll compressors and thermostatic expansion valves.
D) Scroll compressors and electronic expansion valves.
[Ques. 5] Variable refrigerant flow systems operate more efficiently with ________ installed outdoor unit capacity by shifting the heating and cooling to where it is needed.
A) full B) smaller C) larger