Unit Fails To Operate - Nordyne R4GD Series Installation Instructions Manual

blower and combustion blower will continue to run
until the circuit closes. After the safety circuit
closes the main blower and blower will run for a
specified post purge time.
3. The integrated control checks the pressure switch
at the beginning of the heating cycle. If it is closed,
the inducer will run 30 seconds, the control will go
into lock out, and the diagnostic light will flash three
times. If it is open, it will start the inducer motor.
4. The inducer motor starts and closes the pressure
switch. If the pressure switch does not close in 10
seconds the integrated control will go into lock out
and the diagnostic light will flash two times.
5. The inducer will prepurge for 30 seconds and the
igniter will start the warm up cycle as follows.
Initial Power up: After 30 seconds of igniter warm-
up the gas valve (24 VAC) will then open. The igniter
circuit will stay energized for 3 seconds after the gas
valve opens.
After Initial Power up: The control has a programmed
adaptive ignition feature which varies the warm-up
period as follows: If ignition is successful the warm-
up is reduced by 3-seconds on each subsequent
call for heat until ignition failure occurs. Upon ignition
failure, the warm-up is increased by 3-seconds on
the next try. If successful, the timing remains fixed
at this level. In general, whenever ignition failure
occurs the warm-up interval is increased by 3-
seconds on the next try. And if successful, it
remains there. Min. and max. warm-up time limits
are set at 6 and 54-seconds, respectively.
6. The flame must be proven through the flame sensor
in five seconds to hold the gas valve open. The
integrated control will monitor the gas flame with the
flame sensor for the entire time the gas valve is
open. If for any reason the gas flame drops out the
gas valve will immediately close.
7. 30 seconds from the gas valve opening the main
blower starts and continues to run.
8. When the thermostat is satisfied, the "W" terminal on
the integrated control is de-energized.
9. The gas valve circuit is de-energized and the gas
valve closes.
10. The inducer motor will continue to run for the post
purge period of 25 seconds.
11. The main blower will continue to run for the blower off
delay of 120 seconds.
12. After the "blower off" timer has been satisfied, the
integrated control de-energizes the main circulating
blower circuit.
13. If the unit fails to prove ignition after five attempts,
it will go into soft lockout. The unit will re-attempt the
start-up procedure every hour until the thermostat is
satisfied.

Unit Fails to Operate

If the unit does not operate in the cooling mode, be certain
to check the following:
1. The thermostat is operating properly.
2. Electrical power to the unit is turned on.
3. The filters are not dirty.
4. The service doors are in place.
5. The 3 amp fuse is operational.
6. The anti-short cycle timer's 5-minute cycle has
finished for single phase units.
If the unit does not operate in the heating mode, be certain
to check the following:
1. The thermostat is operating properly.
2. Electrical power to the unit is turned on.
3. The filters are not dirty.
4. The gas is turned on.
5. The manual shut-off valve is open.
6. The service doors are in place.
7. The flame roll-out control is closed.
8. Refer to the diagnostic code table on the wiring
diagram or see Table 9.
9. The 5 amp fuse is operational.
FAULT
CONDITION
Power On
Limit Circuit Open
Pressure Switch Stuck Open
Pressure Switch Stuck Closed
Ignition Failure (Check Ground)
230 VAC & Neutral Reversed or No Ground 5 Flash
False Flame or Gas Relay Shorted
Power Off
FAULT
CONDITION
Low Flame Sensor Signal
Flame Present
Table 9. Diagnostic Codes.
STATUS
LIGHT (RED)
On
1 Flash
2 Flash
3 Flash
4 Flash
Continuous Flash
Off
STATUS LIGHT
(YELLOW)
Continuous Flash
On
25