# Heatilator GC112A lighting problems



## DavidM (Dec 16, 2013)

I have a Heatilator GC112A propane fireplace, about 18 years old.  Standing pilot light with wall switch for ignition.  The pilot light sometimes goes out, both when the fireplace is on and when it's off.  Sometimes the fireplace goes out while it's burning.  After waiting a bit, I am usually able to relight the pilot (manual spark ingnition switch) and the fireplace will then light and operate normally, but recently it's been going out several times a day.

Is there a user-replaceable part at or near the pilot that's likely the cause - thermocouple or something along those lines?  Can't afford an expensive service call, but am fairly handy.


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## DAKSY (Dec 16, 2013)

There is probably a thermocouple in the system & It may be ready to fail. If you have a millivolt tester you can use that to see what kind of millivolts it's putting out.  You can usually increase the pilot flame via a screw labeled pilot, but you should have a millivolt tester for that too, so you don't adjust the flame too high. If you can post a picture of both the gas valve & the pilot assembly, that would help...


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## DavidM (Dec 16, 2013)

DAKSY said:


> There is probably a thermocouple in the system & It may be ready to fail. If you have a millivolt tester you can use that to see what kind of millivolts it's putting out.  You can usually increase the pilot flame via a screw labeled pilot, but you should have a millivolt tester for that too, so you don't adjust the flame too high. If you can post a picture of both the gas valve & the pilot assembly, that would help...



I'll try to post a pic later, away at work all day now.  But the pilot flame is burning very strongly - if anything it seems to me that the pilot flame is already too big.


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## DAKSY (Dec 16, 2013)

You say large, but a 1" pilot flame is roughly the right size...The only way to check it is with a multimeter set to Volts DC. If you can look at the tip of the thermocouple, you may be able to tell if it's in bad shape. With LP  you can get carbon build up on the extreme end & when it comes off it'll take some of the casing with it.


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## DavidM (Dec 25, 2013)

DAKSY said:


> You say large, but a 1" pilot flame is roughly the right size...The only way to check it is with a multimeter set to Volts DC. If you can look at the tip of the thermocouple, you may be able to tell if it's in bad shape. With LP  you can get carbon build up on the extreme end & when it comes off it'll take some of the casing with it.



Here are photos of the gas valve and the pilot assembly.  It's still working most of the time, but continues to go out sporadically.  If there's carbon buildup on the  thermocouple can it be cleaned off?


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## DAKSY (Dec 26, 2013)

Looks like it's a thermopile system & doesn't have a thermocouple. Same principle tho. You can try to clean it with stove cleaner to break down the carbon.  Shut the unit down & let it cool. place some newspaper around & under the thermopile to contain the spray & liberally coat the carbon deposit. Wipe it with a cloth...You might use a piece of fine emery do remove whatever doesn't come off from the spraying/wiping. Don't try to chip it off, the thin metal on the OD can be damaged...


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## DavidM (Dec 26, 2013)

DAKSY said:


> Looks like it's a thermopile system & doesn't have a thermocouple. Same principle tho. You can try to clean it with stove cleaner to break down the carbon.  Shut the unit down & let it cool. place some newspaper around & under the thermopile to contain the spray & liberally coat the carbon deposit. Wipe it with a cloth...You might use a piece of fine emery do remove whatever doesn't come off from the spraying/wiping. Don't try to chip it off, the thin metal on the OD can be damaged...


Thanks for the info!  I will try a gentle cleaning - doesn't sound like a replacement thermopile will be hard to obtain or expensive, so I may go ahead and order one to have on hand in case the cleaning doesn't work.  Other than getting that 18 year old nut off the existing thermopile to remove it, it appears to be a simple item to swap out.  I see lots of 750mv replacement thermopiles available online - assume it doesn't necessarily have to be the exact one from Heatilator.


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## DAKSY (Dec 26, 2013)

DavidM said:


> Thanks for the info!  I will try a gentle cleaning - doesn't sound like a replacement thermopile will be hard to obtain or expensive, so I may go ahead and order one to have on hand in case the cleaning doesn't work.  Other than getting that 18 year old nut off the existing thermopile to remove it, it appears to be a simple item to swap out.  I see lots of 750mv replacement thermopiles available online - assume it doesn't necessarily have to be the exact one from Heatilator.


 
Probably can use one from just about anywhere. True Value has them for about $50...They call em Universal Millivolt Generators...


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## DavidM (Dec 26, 2013)

DAKSY said:


> Probaly can use one from just about anywhere. True Value has them for about $50...They call em Universal Millivolt Generators...


Found this one on Amazon for $22 - not sure about the push-in clip vs. the threads, but maybe the push-in is a better way to go for the replacement anyway :  http://smile.amazon.com/Honeywell-C...Generator/dp/B000BQK5H6/ref=cm_cmu_pg__header


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## DAKSY (Dec 26, 2013)

DavidM said:


> Found this one on Amazon for $22 - not sure about the push-in clip vs. the threads, but maybe the push-in is a better way to go for the replacement anyway :  http://smile.amazon.com/Honeywell-C...Generator/dp/B000BQK5H6/ref=cm_cmu_pg__header


 
 That'll probably work. If the push up clips don't hold it in position, re-use the nut from the original...


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## canucklehead (Jan 3, 2014)

Wow, this is very similar to my issue. My elderly Aunt has a Heatilator model GC341, made in 11/94. Hasn't really been used that much as she was away most winters until her health stopped snowbirding. It is a Natural Gas model, not propane. Uses piezo ignitor to light pilot.

Her pilot goes out same as you described...could be during full burn with heater on, or with only pilot lit. I took it apart and cleaned up pilot (I thought I cleaned the "thermocoupler" rod...I think some call it the flame rod). The pilot burns nice and blue and is correct size.

She can't afford a service call. Maybe I could replace the thermocoupler? I was wondering if gas valve causes this?

thanks!!


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