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441 01 2611 06
14. Sequence of Operation & Diagnostics
The following is the normal operating s equence.
Cooling (Y) Request:
24 VAC signals applied to Y & G terminals of EFT (electronic fan timer) control.
· Cool motor s peed is energized after 5 second Cool Fan On Delay time.
Y & G signals removed from EFT.
· Cool motor speed is de--energized after 90 second Cool Fan Off Delay time.
Continuous Circulating Fan (G) Request:
24 VAC signals applied to G terminals of EFT control.
· Heat motor speed is energized without delay .
G signal removed from EFT.
· Heat motor speed is de--energized without delay.
NOTE 1) Furnace de--energizes the fan during the heat exchanger warm--up period on a call for Heating that occurs during a G
request unless a blower motor lead is connected to the Cont terminal on the EFT, in which case see NOTE 2).
NOTE 2) Heating or Cooling requests received during a Fan request cause the fan speed to change to the appropriate heat or cool
speed after the Fan On Delay time expires. The fan returns to continuous circulating speed after the selected Fan OffDelay time ex-
pires following loss of the Heating or Cooling request.
Heating (W) Request:
24 VAC signals applied to W terminal of EFT control.
· Inducer motor turns on.
· Followinga3secondprepurge delay, the pilot gas valve opens and the igniter begins to warm up.
· After the pilot lights, the gas control v alve is energized and main burners light.
· Timed from the opening of the main gas control valve, the furnace control will delay blower operation for the Heat Fan On Delay
time. W signal removed from EFT.
· The gas valve de--energizes and the main burners go out.
· The inducer runs for a 30 second postpurge period.
· The fan stays at Heat speed.
· Timed from the gas valve de--energizing, the circulating fan de--energizes after the selected Heat Fan Delay time expires.
Heating Request with Gas Shut Off:
24 VAC signals applied to W1 terminal of EFT c ontrol.
· Inducer motor turns on.
· Followinga3secondprepurge delay, the pilot valve opens and the igniter begins to warm up.
· The igniter glows red--hot for 30 seconds, then turns off.
· The igniter stays off for 25 seconds, then begins to warm--up again.
· The igniter glows red--hot for 30 seconds, then turns off.
· The pilot valve closes 3 seconds after the igniter de--energizes.
· The inducer de--energizes 5 seconds after the pilot valve closes.
· The SmartValve proceeds to soft lockout and flashes error code 6.
· The control exits soft lockout after 5 minutes and begins another ignition sequence.
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