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Discussion Starter · #1 ·
I don't want to fix this myself, but I do want to educate myself on the source of the problem before I call for a service tech.

I have a Slant/Fin Galaxy GG125 boiler (installed 1985) that has an intermittent pilot light. At least, it used to be intermittent!

For the past few days, the intermittent pilot has been staying lit 24/7, after the main burner shuts off.

The pilot even stays lit when I switch the knob on the gas valve to "off".

If I shut the main gas supply off, it goes out. When I start it up again after this, it sparks, pilot lights, and main burners come on. However, when main burners shut off, the pilot stays on again indefinitely.

Boiler is otherwise cycling properly.

Is this a defective intermittent pilot control? Or a defective gas valve?

Thanks
 

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The gas valve should not allow the pilot to remain lit when mechanically turned to the off position. If you are sure that you have moved the gas valve control to the off position, and the pilot remains on....
change the gas valve.
 

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Discussion Starter · #4 ·
Sticking gas valve? Or faulty control?

Thanks for the feedback.

Ok - I just double checked and it looks like I did not shut the gas valve knob control all the way off the first time. When I shut it all the way off, the pilot does indeed go out.

But the pilot flame is still staying on continuously between cycles, when there is no call for heat.

I experimented by blowing out the pilot flame. The pilot valve stayed open, and gas continued to flow despite the lack of flame. This continued for about 30 seconds, until I re-lit the pilot manually with a match.

The valve is a White-Rodgers 36C84, Type 201, with a White Rodgers 3098-134 Automatic Pilot flame sensor that plugs into it.

Sticking gas valve? Or faulty control?
 

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Most likely gas valve. To check, use a multimeter to see if you have 24 volts going to the gas valve's pilot terminal. if not, its the gas valve, if you do, its the control.

Either way, you have an unsafe unit, and should shut the gas off until fixed.
 
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