GSX14 Service Manual

SERVICING
143
The air handler/modular blower is commanded to end
auxiliary heat operation. The air handler control de-
energizes the electric heat sequencer outputs. The
ECM blower motor remains energized until any blower
OFF delay timing has expired.
Outdoor Temperature Below the Heat Pump Balance
Point
2.1 The CTK0*** thermostat sends a request for the outdoor
air temperature to the heat pump. The heat pump returns
an outdoor air temperature that is below the balance
point temperature. Heat pump heating is disabled.
2.2 The CTK0*** thermostat sends a request for auxiliary
heat to the air handler/modular blower.
2.2 The air handler control energizes the ECM blower motor
at the auxiliary heat speed. The electric heat sequencer
outputs are also energized, thus energizing the electric
heaters.
2.3 The system operates at auxiliary heat.
2.4 Once the thermostat demand is satisfied, the CTK0*
thermostat commands the air handler/modular blower to
end auxiliary heat operation. The air handler control de-
energizes the electric heat sequencer outputs. The
ECM blower motor remains energized until any blower
OFF delay timing has expired.
3.0 Continuous Fan Operation
3.1 With a demand for continuous fan operation, the CTK0*
thermostat sends a fan request to the integrated air
handler control along with a fan demand. The
controladjustable via the CTK0* thermostat. The com-
pressor delay is intended to eliminate compressor noise
during the reversing valve shift.) The compressor will
energized (or re-energized) at high stage.
3.2 If the thermostat demand for continuous fan is removed,
the CTK0* thermostat commands the integrated air
handler control to end continuous fan operation. The
integrated AH control immediately de-energizes the
ECM blower motor.
4.0 Defrost Operation
4.1 While the system is operating in heat pump heating (see
2.0 Heating Operation), the control in the outdoor unit
may determines that a defrost cycle is needed. Upon
determing that a defrost cycle is needed, the UC control
de-energizes the condensor fan motor and energizes the
reversing valve.
4.2 The compressor may be de-energized for a short delay
during the reversing valve shift. (The delay period is
adjustable via the CTK0* thermostat. The compressor
delay is intended to eliminate compressor noise during
the reversing valve shift.) The compressor will energize
(or re-energize) at high stage.
4.3 The UC control sends a request for defrost operation to
the integrated air handler control. The air handler control
energizes the electric heat sequencer outputs and
operates the ECM blower model at the electric heat
speed.
4.4 Once the defrost cycle is terminated, the heat pump
commands the air handler/modular blower to end defrost
operation.
4.5 The system returns to heat pump heating operation that
was in effect prior to the defrost cycle.
5.0 Emergency Heat Operation
5.1 The CTK0* thermostat sends a request for emergency
heat to the air handler/modular blower.
5.2 The air handler control energizes the ECM blower motor
at the emergency heat speed. The electric heat se-
quencer outputs are also energized, thus energizing the
electric heaters.
5.3 The system operates at emergency heat.
5.4 Once the thermostat demand is satisfied, the CTK0*
thermostat commands the air handler/modular blower to
end emergency heat operation. The air handler control
de-energizes the electric heat sequencer outputs. The
ECM blower motor remains energized until any blower
OFF delay timing has expired. energizes the variavble
speed ECM motor at fan demand provided by the thermo-
stat. The fan demand provided by the thermostat will be
30%, 50%,or 70% of the air handler's maximum airflow
capability. The continuous fan demand is set from the
thermostat as low, medium, or high.
S-50 CHECKING HEATER LIMIT CONTROL(S)
(OPTIONAL ELECTRIC HEATERS)
Each individual heater element is protected with an automatic
rest limit control connected in series with each element to
prevent overheating of components in case of low airflow.
This limit control will open its circuit at approximately 150°F.
to 160°F and close at approximately 110°F.
WARNING
Disconnect ALL power before servicing.
1. Remove the wiring from the control terminals.
2. Using an ohmmeter test for continuity across the normally
closed contacts. No reading indicates the control is open
- replace if necessary. Make sure the limits are cool
before testing.
IF FOUND OPEN - REPLACE - DO NOT WIRE AROUND.
S-52 CHECKING HEATER ELEMENTS
Optional electric heaters may be added, in the quantities
shown in the spec sheet for each model unit, to provide
electric resistance heating. Under no condition shall more
heaters than the quantity shown be installed.