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Alert 08-31-2011 04:39 PM

Thermocouple Replacement Works Briefly
I have a Utica MGB150HD. It's about ten years old. The pilot light will not stay lit. I replaced the thermocouple unit about two months ago and it worked fine until this past weekend. I replaced the thermocouple again and it worked fine for two days.

Now the pilot will again not stay lit. I can get it to light and run through a cycle (after many tries) but the pilot always goes out shortly after it cycles.

Any ideas?


REP 08-31-2011 08:28 PM

my first thought is that you are using cheap thermocouples.
Get yourself some good Penn thermocouples or at the very least Honeywell.
My second thought is that maybe the pilot itself need cleaning especially the pilot orfice.

Alert 08-31-2011 08:34 PM

The replacement thermocouples are Honeywell.

When the pilot is on, it's a very strong flame coming out of both sides of the "T" shaped end. So there doesn't seem to be any kind of obstruction in the gas line.

REP 08-31-2011 08:41 PM

Is the tip of the thermocouple engulfed in the flame.the last 1/2 inch like the instruction shows?Also yoyu can over tighten the thermocouple and crush the end that touches the gas valve.
outside of that,you probably need a new gas valve.

Alert 08-31-2011 10:47 PM

Thanks for your answers, I appreciate the help.

It looks like I have a Honeywell VR8200A2132 Dual Standing Pilot Gas Valve.

These are available online for $89.

Is it beyond a beginner like myself to install one of these?

Installing the thermocouple units was my first attempt at furnace repair.

I'm afraid it will be a $500 job if I call a plumber.

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