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The Right Fit For Comfort
12
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FAN PURGE (Optional)
After the room thermostat has been satisfied, the purge
feature allows the indoor fan to remain on for an additional
60 seconds. This increases efficiency by pulling the
remaining energy from the unit.
COOLING OPERATION
After connecting the thermostat to the unit place the system
switch in
cool
mode. Adjust the set-point temperature
below the room temperature. The compressor and fan
motors will start and cooling will begin. Place the set-point
temperature above the room temperature. The compressor
and condenser fan will stop and the indoor fan will remain
on for an additional sixty seconds.
the set-point remains above room temperature. Next place
the set-point temperature below room temperature. The
Electric heater will switch off and the indoor fan will remain
on for an additional sixty seconds.
HYDRONIC HEAT OPERATION (Optional)
An optional hydronic heat package may be selected in
lieu of electric heat. Heating operation is essentially the
same as that of units with electric heat. With the thermostat
system switch
set to
heat
and the set-point temperature
above room temperature, the hydronic valve will open
allowing water to flow through the coil. The indoor fan will
also switch on and warm air will flow from the unit. Heating
will continue so long as the set-point remains above room
temperature. Place the set-point temperature below room
temperature. The hydronic valve will close and indoor fan
will switch off after the sixty-second purge time has
elapsed. The hydronic valve is a 24Vac normally open
valve. Should power be lost to the unit, the valve will default
to the open position.
HEAT PUMP (Cooling Mode)
Cooling operation in a heat pump unit is described in
“Cooling operation” above. The unit is equipped with a
reversing valve that is energized for cooling and de-
energized in heating mode.
HEAT PUMP (Heating Mode)
Heat pump units are “Limited Range” equipped with back-
up electric resistance heat. Limited Range heat pumps
are designed to operate when outdoor temperatures are
between 75°F and 40°F and with a maximum indoor
temperature of 80°F. When the outdoor temperature falls
below approximately 40°F the unit will switch from heat
pump to electric resistance heat. Electric heat will then
remain as the heat source until the outdoor temperatures
rise above 50°F. Retroaire heat pumps (RH – PTHP) are
single-stage heating units. The electric heat and heat pump
will NOT operate simultaneously.
To operate the unit in heating mode, it must first be
connected to an appropriate heat pump thermostat. (See
choosing a thermostat). Select
heat
on the thermostat
system switch. Then, adjust the set-point temperature
above the room temperature. The compressor and fan
motors will start and heating will begin. If the outdoor
temperature is below approximately 40°F the heat pump
system will not operate. Electric heat will then take over
the heating demand. Heating will continue so long as the
set-point temperature remains above the room
temperature. Place the set-point temperature below the
room temperature. The heating mode will cease and the
indoor fan will remain on for an additional sixty seconds.
NOTE:
The start of the compressor will not take place
until the anti-short/random start time period has elapsed.
HEAT PUMP (Emergency Heat)
WARNING!
Before accessing the control compartment, discon-
nect power to the unit. Failure to do so could result in
serious injury or electrical shock.
Should the heat pump system fail, it is possible to force
the control board into electric heat mode. This is a tempo-
rary solution until the heat pump system can be repaired.
Locate the circuit board in the control section of the unit.
Locate the terminals where the outdoor sensor connects to
the circuit board. Using a small needle nose type pliers,
disconnect one side of the sensor from the circuit board.
This will appear to the circuit board as an outdoor coil
freeze condition there-by energizing the electric resistance
heater on the call for heat.
RETROAIRE PTAC OPERATION (Continued)
