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No heat - Honeywell S8610U error: "Flame sensed out of sequence"

10297 Views 3 Replies 2 Participants Last post by  yuri
Tenants called me over and said heater was blowing cold air.

Removed cover and saw the pilot flame was lit. The ignition control module is flashing 6+4, which according to the troubleshooting list is "Flame sensed out of sequence - longer than 10 seconds".

From the manual:

Honeywell S8610U 3009

Next system action:

Control waits until flame is no longer sensed and then goes to soft lockout. Flash code continues. Control auto resets from soft lockout after one hour.

Recommended service action:

Check for pilot flame. Replace gas valve if pilot flame present. If no
pilot flame, cycle "Call for Heat" If error repeats, replace control.
I turned the unit off, to see if anything changes after an hour. I am about to go over and see if i can clean the flame sensor.

Wanted to throw this out here now in case anyone has some advice. The manual says that if the pilot flame is present (which it is), that the gas valve should be replaced. Would this be the correct thing to do, or should i do additional troubleshooting?

Thanks for any help!
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If the pilot is stuck on then either the gas valve pilot valve is stuck open which is very rare ( never seen it) or you are getting 24 volts from the S86 to the PV terminal on the valve. Pull the PV wire off the valve and see if the pilot goes out and check it for 24 volts to C.

If it stays on the the valve is bad.
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You know yuri, i think it might have been stuck open. I've replaced a gas valve before, and done some basic troubleshooting, but couldn't remember if the pilot was supposed to stay lit constantly like it was. I'm assuming it isn't supposed to stay lit?

Here's what i did... I turned the thermostat off (pilot remained on), and hit the gas valve a few times with a rubber mallet... the pilot went out and i thought 'oh well thats great now i messed up the pilot light also'. However, now i realize that the pilot light going off might have been the desired result. Anyway, when i turned the thermostat back on, the heater fired back up like normal. So it looks like the valve is starting to stick... i suppose i should start looking at ordering a new one and replacing it.

The codes on the ignition control went back to flashing a heartbeat, which is normal operation.

Thanks for your input.
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Yeah I don't see many older units with the S86 anymore other than the Lennox Whisperheat. After 20-25 yrs most furnaces get replaced where I am.
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