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13HPD SERIES
During the defrost cycle, you may notice steam rising
from the outdoor unit. This is a normal occurrence. The
thermostat may engage auxiliary heat during the
defrost cycle to satisfy a heating demand; however,
the unit will return to normal operation at the
conclusion of the defrost cycle.
EXTENDED POWER OUTAGE RESTART
PROCEDURE
If the outdoor temperature is below 50°F (10°C) and power
to your outdoor unit has been interrupted for six hours or
longer, observe the following when restoring power to your
heat pump system.
Set the room thermostat selector to the EMERGENCY
HEAT setting to obtain temporary heat for a minimum
of six hours. This will allow system refrigerant
pressures and temperatures enough time to return to
a stabilized condition.
In Emergency Heat mode, all heating demand is
satisfied by auxiliary heat; heat pump operation is
locked out. After a six-hour warm-up period, the
thermostat can then be switched to the HEAT setting
and normal heat pump operation may resume.
NON−PROGRAMMABLE THERMOSTAT OPERATION
Though your thermostat may vary somewhat from the
description below, its operation will be similar.
Temperature Setting Levers
Most heat pump thermostats have two temperature
selector levers: one for heating and one for cooling. Set the
levers or dials to the desired temperature setpoints for both
heating and cooling. Avoid frequent temperature
adjustment; turning the unit off and back on before
pressures equalize puts stress on the unit compressor.
Fan Switch
In AUTO or INT (intermittent) mode, the blower operates
only when the thermostat calls for heating or cooling. This
mode is generally preferred when humidity control is a
priority. The ON or CONT mode provides continuous
indoor blower operation, regardless of whether the
compressor or auxiliary heat are operating. This mode is
required when constant air circulation or filtering is desired.
System Switch
Set the system switch for heating, cooling or auto
operation. The auto mode allows the heat pump to
automatically switch from heating mode to cooling mode to
maintain predetermined comfort settings. Many heat
pump thermostats are also equipped with an emergency
heat mode which locks out heat pump operation and
provides temporary heat supplied by the auxiliary heat.
Indicating Light
Most heat pump thermostats have an amber light which
indicates when the heat pump is operating in the
emergency heat mode.
Temperature Indicator
The temperature indicator displays the actual room
temperature.
PROGRAMMABLE THERMOSTATS
Your Lennox system may be controlled by a
programmable thermostat. These thermostats provide the
added feature of programmable time-of-day setpoints for
both heating and cooling. Refer to the user’s information
manual provided with your particular thermostat for
operation details.
PRESERVICE CHECK
If your system fails to operate, check the following before
calling for service:
Check to see that all electrical disconnect switches are
ON.
Make sure the room thermostat temperature selector
and system switch (HEAT, COOL and AUTO) are
properly set.
Check for any blown fuses or tripped circuit breakers.
Make sure unit access panels are in place.
Make sure air filter is clean.
If service is needed, locate and write down the unit
model number and have it handy before calling.
