10. Sequence of Operation & Diagnostics

The following is the normal operating sequence for the control system.

Cooling (¥) Request:

24 VAC signals applied to Y & G terminals of EFT (electronic fan timer) control.

•Cool motor speed energized after 5 second Cool Fan On Delay time.

Y & G signals removed from EFT.

•Cool motor speed de-energized after 90 second Cool Fan Off Delay time.

Circulating Fan (G) Request:

24 VAC signals applied to G terminals of EFT control.

•Heat motor speed energized without delay.

G signal removed from EFT.

•Heat motor speed de-energized without delay.

Heating (W) Request:

24 VAC signals applied to W terminal of EFT control.

•Inducer motor turns on.

•The gas valve solenoid energizes.

•Following a 3 second prepurge delay, the pilot valve opens and the ignitor begins to warm up.

•After the pilot lights, the main burners energize and light.

•Timed from the opening of the main gas valve, the control will delay 30 seconds before switching the fan to Heat speed.

W signal removed from EFT.

•The gas valve de-energizes and the main burners go out.

•The inducer runs at its present speed for a 30 second postpurge period.

•Timed from the gas valve de-energizing, the Heat fan speed de-energizes after the selected Heat Fan Delay time expires.

Heating Request with Gas Supply Line Shut Off:

24 VAC signals applied to W terminal of EFT control.

•Inducer motor turns on.

•The gas valve solenoid energizes.

•Following a 3 second prepurge delay, the pilot valve opens and the ignitor begins to warm up.

•The ignitor 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.

44001 102004

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Sears N9MP2100J20B1 manual Circulating Fan G Request, Heating W Request, Heating Request with Gas Supply Line Shut Off
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9MPD100J20B1, N9MP2100J20B1, 9MPD050F12B1, N9MP1100J20B1, N9MP1125J20B1 specifications

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