unit 43

What prevents cold air from being circulated to the heated space during the defrost cycle?

• The auxiliary heater turns on to "temper" the air.

• All of the dampers close automatically

• The indoor fan motor turns off

• Both a and b are correct

The main valve in a 4-way reversing valve is moved by pressure created by ____.

• refrigerant boiling in the coil

• pressure reduction in the condenser

• change in the action of the metering device

• low and high side pressure difference.

Termination of the defrost cycle occurs when the liquid off the outside coil reaches ____.

• 35°F

• 45°F

• 50°F.

• 65°F

The suction line is connected between the ____.

• inside and outside coil outlets

• inside and outside metering devices

• compressor and the defrost relay

• compressor, accumulator, and reversing valve.

The hot gas line is always connected between the ____.

• compressor and the condenser

• reversing valve and the condenser

• reversing valve and the accumulator

• compressor and the reversing valve.

A pressure-temperature defrost control is activated by the ____.

• difference of the pressure in the fan compartment and the temperature of the coil

• difference in pressure between the outdoor pressure and the fan discharge pressure

• difference in the pressure of the air through the outdoor coil.

• difference in pressure of the refrigerant in the condenser and the pressure in the coil

In the emergency heat mode, the auxiliary heat source becomes the primary heat source and the compressor is disabled.

• True.

• False

It is common for the outdoor unit to ice-up when the heat pump is operated in the cooling mode.

• True

• False.

During operation, the compressor motor will rotate in the opposite direction to change the direction of refrigerant flow.

• True

• False.

In a heat pump system, the indoor and outdoor coils are almost the same size.

• True

• False.