No Heat


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Old 10-16-06, 04:20 AM
L
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No Heat

Good morning! I am working on a friends gas furnace. The furnace will not light. Upon checking, I traced the wiring through the system and I have 24v at the "heat" wire at the board....power then flows to a air pressure switch for the combustion vent blower....from there I was getting fluctuating readings of 70 - 90v. If I disconnect the Honeywell Intermittant Pilot Module, the 24v returns...it only goes high once the module is connected. I also disconnected the harness from the module to the gas valve and voltage still stayed high and fluctuated. I got a new module Saturday and hooked it up.....24v stays constant but the new module won't spark. The original module was a Honeywell S86001005 and the replacement is a S8610U....looks the same except it has a "jumper" plug for a vent damper and also a terminal (wired) for "sense". Can anybody give me a clue with what may be wrong...I'm assuming I have a bad new module. Could a bad gas valve cause the voltage problems? Thanks for the help!
 
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Old 10-16-06, 07:44 PM
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You got an odd event going on here.

Is the combuston blower running?
 
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Old 10-17-06, 04:09 AM
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Thanks for the reply Jay11J....actually, I got it fixed yesterday....the problem was the pilot orifice clogged up. I also got a good lesson in the proper use of a voltmeter...should have checked voltage ACROSS the terminals rather than from ground to terminal. After working on it Saturday afternoon, worrying about it all day Sunday, losing sleep over it Sunday night, it sure was a good feeling to hear that familiar "whosh" once it ignited! Turns out however the new module I purchased was bad (blown fuse internally) so I had to re-install the old module that works fine.
 
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Old 10-17-06, 08:17 AM
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Glad to hear you got it going, and got it cleaned. Don't forget to keep the air filter clean too.
 
 

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