Sears N9MP2, N9MP1, 9MPD manual Honeywell SV9541M

HONEYWELL SV9541M

IPOWERAPPLIEDTO APPLIANCE

+

I THERMOSTATCALLS FORHEAT

¢

IPRESSURE SWITCHES PROVED OPEN?

ICOMBUSTIONBLOWER ENERGIZED

PRESSURESWITCHESCLOSEDWITHIN30 SEC- ONDS?

+

I3SECONDPRE-PURGE

PILOTVALVEOPENS: IGNITORPOWERED(1)

PILOTLIGHTSAND FLAME ISSENSED DURING 90SECOND TRAILFOR IGNITION?

I YES

MAIN VALVEOPENS,

HEATINGFAN "ON" DELAYBEGINS

+

I AFTERDELAY:CIRCULATINGBLOWERSTARTS

FLAME SENSE LOST?

"SMART VALVE" Sequence of Operation

I

WAIT FORPRESSURESWITCHESTO OPEN

_._ COMBUSTIONBLOWER DE-ENERGIZED J__ FIVEMINUTE WAIT PERIOD

I

FAILURETHREESECONDFLAMERECYCLEDELAY,J_

l'_Vl PILOTVALVECLOSES;
PILOT IGNITOROFF	r

I

YES

			CIRCULATINGBLOWEROFF AFTER DELAY
I	I		+
	PILOTAND MAIN VALVECLOSE	1

THERMOSTATCALL FORHEAT ENDS

L FLAMETIMES INSENSETHISCALLLOSTFORHEAT?MORETHAN FIVE

COMBUSTIONAIR BLOWER OFF AFTERPOST

PURGE

NO

PILOTAND MAIN VALVECLOSE

+

COMBUSTIONBLOWER DE- ENERGIZEDAFTER 30

SECONDPOST PURGE

+

I CIRCULATINGBLOWEROFF AFTER DELAY

I

IWAIT FOR NEXTCALL FOR HEAT

I

NO

YES

(1) Ignitor "ON" for first 30 seconds of trial for ignition, then "OFF" for next 30 seconds. If the pilot has not lit, it turns back "ON" for the final 30 seconds. The pilot valve remains energized during the entire 90 second trial for ignition.

NOTE: If main limit string opens and takes longer than 2 minutes to close, system goes into I hour wait

period.

I

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