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SEQUENCE OF OPERATION
Cooling (cooling only or heat pump)
Single Stage Cooling
For single stage cooling, Y1 and Y2 need to be jumpered.
When the thermostat calls for cooling, the circuit between R
and G is completed, and the blower relay is energized. The
Normally Open contacts close, causing the indoor blower
motor to operate. The circuit between R and Y is also
completed; this circuit closes the contactor in the outdoor
unit starting the compressor and outdoor fan motor. Circuit
R and O energizes the reversing valve switching it to the
cooling position. (The reversing valve remains energized as
long as selector switch is in the COOL position.)
Two Stage Cooling
On a call for 1
st
stage cooling, the thermostat closes R to
Y. In 1
st
stage cooling, the blower runs at 70% of the
selected cooling airflow. On a call for 2
nd
stage cooling, the
thermostat closes R to Y2. In 2
nd
stage cooling, the blower
runs at 100% of the selected cooling airflow.
Heating (electric heat only)
When the thermostat calls for heat, the circuit between R
and W is completed, and the heater sequencer is ener-
gized. A time delay follows before the heating elements
and the indoor blower motor come on. Units with a second
heat sequencer can be connected with the first sequencer
to W on the thermostat sub-base or connected to a
second stage on the sub-base.
Heating (heat pump)
When the thermostat calls for heat, the circuits between R
and Y and R and G are completed. Circuit R-Y energizes
the contactor starting the outdoor fan motor and the
compressor. Circuit R and G energizes the blower relay
starting the indoor blower motor.
If the room temperature should continue to fall, the circuit
between R and W1 is completed by the second stage heat
room thermostat. Circuit R-W1 energizes a heat se-
quencer. The completed circuit will energize supplemental
electric heat. Units with a second heater sequencer can
be connected with the first sequencer to W1 on the
thermostat or connected to a second heating stage W2 on
the thermostat sub-base.
Emergency Heat (heating heat pump)
If selector switch on thermostat is set to the emergency
heat position, the heat pump will be locked out of the
heating circuit, and all heating will be electric heat. A
jumper should be placed between W2 and E on the
thermostat sub-base so that the electric heat control will
transfer to the first stage heat on the thermostat. This will
allow the indoor blower to cycle on and off with the electric
heat when the fan switch is in the AUTO position.
