Unit 43 Air Source Heat Pumps

The temperature of the heated airstream from a heat pump operating in the heating mode under typical conditions is approximately _________________.

100 °F

Most heat pumps require a minimum of ____________of capacity in the cooling mode.

400 cfm/ton

Termination of the defrost cycle by temperature occurs when the temperature sensor reaches ____.

50°F

Metering devices in most heat pumps are piped in parallel with a(n) _____________________.

Check Valve

The ratio of usable output energy divided by input energy.

Coefficient of Performance (COP)

The term used in comfort heating to describe a cold outside wall and its effect on human comfort.

Cold Wall

A refrigeration system used to supply heat or cooling using valves to reverse the refrigerant gas flow

Heat Pumps

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

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

When brazing a four-way reversing valve, __________could be wrapped around the body of the valve to minimize the chance of internal damage to the valve.

a wet rag

The term ____________________ indicates the source of heat while the system is operating in the heating mode and the medium that is ultimately being treated.

air-to-air

In the emergency heat mode, the ___________________ becomes the primary heat source because of heat pump failure.

auxiliary heat source

Some heat pump systems when not capable of meeting the heating needs of the structure are equipped with second-stage heat, called ____________________.

auxiliary-heat

The lowest outside air temperature at which the heat pump system can satisfy the heating needs of the structure without requiring auxiliary heat is called the ____________________.

balance-point

A(n) ____________________ thermostatic expansion valve has a check valve built into the body of the TXV.

bi-directional

Filter-driers installed in heat pump systems should be of the ________________ type or installed with check valves.

biflow

The coil of the air-to-air heat pump system that is the indoor unit is known as the ____________________ in the heating mode.

condenser

The coefficient of performance of a heat pump operating in the heat mode tends to ____________________ as the outside air temperature drops.

decrease

When oil or gas auxiliary heat is used with a heat pump, the heat pump indoor coil must be located ____________________ of the oil or gas heat exchanger.

downstream

The coil of the air-to-air heat pump system that is the indoor unit is known as the ____________________ in the cooling mode.

evaporator

Most heat pump systems are designed to operate in the heating mode when the solenoid is not energized. This is referred to as "____________________ in the heating mode".

failing

The component used to switch the heat pump unit between the heating and cooling modes of operation is the ____.

four-way valve

The ____________________ is a four-port valve that has a slide mechanism in it.

four-way-reversing-valve

The larger line in an air-to-air split-system heat pump is known as the ____ line.

gas

When a heat pump is added to an electric furnace, the indoor coil must be located after the ____________________ strips.

heat

The coil that serves the inside of the house in a heat pump is known as the ____________________.

indoor-coil

When orifice metering devices are used in heat pump, the one at the indoor coil has a _________________ than the one at the outdoor coil.

larger bore

The smaller line in an air-to-air split-system heat pump is known as the ____ line.

liquid

The main valve in a pilot-operated four-way reversing valve is moved by pressure created by the ____.

low and high side pressure difference

The Capillary tube is used in some older heat pumps as the__________________.

metering device

A common method of starting defrost uses an air pressure switch that measures the difference in pressure ____.

of the air across the outdoor coil

In time-temperature defrost controls, the temperature that actuates the control is the temperature of the ____________________ coil.

outdoor

A common metering device is a combination flow device and check valve. This device is referred to as a(n) ____________________.

piston

The water-to-air heat pump might not need auxiliary heat because the water can be at _______________ all winter.

relatively constant temperature

An air-to-air heat pump ____ heat from the outside air and deposits it in the conditioned space.

removes

In heat pump systems the sensing bulb is typically exposed to high temperatures and could rupture the valve diaphragm. For this reason, a(n) ____________________ TVX is usually used.

vapor-charged