Heat Pumps Pay Their Own Way - Carrier 52S Architects And Engineers' Manual

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.
How The Heat Pump Works
In Hot Weather:
Carrier's Series 52S series units
provide indoor comfort in the
same manner as conventional air
conditioners, removing heat and
humidity from indoor air. The
heat and humidity is released to
the outdoors. Carrier's high effi-
ciency design saves energy and
reduces cooling costs.
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 temperature. It switches the unit to
electric heat mode when the outdoor temperature is
25 F or below. The thermostat switches the unit back
to heat pump mode when the outdoor temperature
rises above 40 F, which is enough to provide heat to
meet demand. The entire operation is completely
automatic.
In Cool Weather:
When the outdoor temperature is
above 25 F, the heat pump draws
heat from outdoor air and uses it
to heat indoor air. Since heat is
transferred and not produced,
Carrier's heat pump uses less
electricity and reduces energy
costs significantly.
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.
9
In Sub-Freezing Weather:
When the outdoor temperature
falls below 25 F, the unit auto-
matically switches on a built-in
electric heater. The compressor
stops and a blower circu-
lates warm air produced by the
heater. When the
temperature rises above 40 F,
heat pump operation resumes
automatically.
outdoor