Carrier 592-085 warranty Heat Pumps Pay Their Own Way, Special Features, How The Heat Pump Works

PRODUCT FEATURES AND BENEFITS (cont)

HEAT PUMPS PAY THEIR OWN WAY

Heat pump models are available at a nominal addi- tional cost. In many locales, the payback is realized in just a few months. Cost and payback details are pro- vided on the next page.

Special Features

Two-Stage Indoor Thermostat:

The indoor thermostat senses the indoor temperature and automatically turns on the electric heat to warm the room quickly. After the desired temperature condi- tions have been satisfied, the thermostat automatically switches to heat pump mode. If compressor failure occurs, the thermostat will provide backup electric heat automatically.

Outdoor Thermostat:

During the heating cycle, the outdoor thermostat senses outdoor coil temperature. It switches the unit to electric heat mode when the outdoor coil temperature is 20 F or below (approximately 35 F outdoor-air tem- perature). The thermostat switches the unit back to heat pump mode when the outdoor coil temperature rises above 40 F, which is enough to provide heat to meet demand. The entire operation is completely automatic.

Reversing Valve:

The reversing valve provides quiet refrigerant flow after the unit shuts off. The valve controls the direction of refrigerant flow for both heating and cooling func- tions and remains energized as long as the controls are in the heat position. When the cooling controls are activated, the valve automatically reverses to the cool- ing position.

Manual Compressor Override Switch:

This switch completely locks out the compressor. Note that the compressor and heater do not operate at the same time, thus conserving energy.

How The Heat Pump Works

In Hot Weather:

Carrier’s PTAC units provide indoor comfort in the same manner as conventional air conditioners, remov- ing heat and humidity from indoor air. The heat and humidity is released to the outdoors. Carrier’s high- efficiency design saves energy and reduces cooling costs.

In Cool Weather:

When the outdoor coil temperature is above 20 F (approximately 35 F outdoor-air temperature), the heat pump draws heat from outdoor air and uses it to heat indoor air. Since heat is transferred and not pro- duced, Carrier’s heat pump uses less electricity and reduces energy costs significantly.

In Sub-Freezing Weather:

When the outdoor coil temperature falls below 20 F (approximately 35 F outdoor-air temperature), the unit automatically switches on a built-in electric heater. The compressor stops and a blower circulates warm air produced by the heater. When the outdoor coil temperature rises above 40 F, heat pump operation resumes automatically.

12