# Fireplace pilot light won't stay lit



## jgdickjr (Jan 17, 2009)

I'm looking for some input from an "experienced gas specialist!!  I have a Majestic DVBR36 Direct Vent Fireplace about 2 years old with very low hours on it.  It worked fine last year but over the summer I turned off the gas and thus the pilot light.  NOw, the pilot light won't sray lit after I release the "pilot" button.  The ignitor works fine and the flame envelops the thernocouple and thermopile fine I think.  I even used a propane torch to add some extra heat but no joy so I have ruled out a flame problem. It uses a Honeywell Millivolt Hi-Low gas valve ((VS8420) with a remote wall switch (no thermostat)  I checked the switch and it and the wires are OK.  The thermopile (connected to terminals TH and TDTH) puts out 470 mv after 30 seconds and 750 mv after 1 minute.  The thermocouple puts out 220 mv after 30 seconds and 350 mv after 1 minute.  These seem Ok based on what I'v been able to gather from manual and the internet.  I'm about ready to order a gas valve but am looking for confirmation from an expert.  Help Please!!


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## R&D Guy (Jan 17, 2009)

Sounds like the valve to me.  You might want to make a short jumper and jump the wall switch just to be sure.  Also, try taping on the valve with the handle side of a screw driver.  If it kicks on then you know its the valve although you'll still need to replace it as the problem will come back.


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## trafick (Jan 18, 2009)

You said, "Now the pilot light won't stay lit after I release the "pilot" button".  Well I'm certainly no expert but this sounds like the classic bad thermocouple problem to me.

I would try that before I replaced the gas valve.  Probably a lot less expensive.


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## R&D Guy (Jan 18, 2009)

trafick said:
			
		

> You said, "Now the pilot light won't stay lit after I release the "pilot" button".  Well I'm certainly no expert but this sounds like the classic bad thermocouple problem to me.
> 
> I would try that before I replaced the gas valve.  Probably a lot less expensive.



That's what I thought at first, but it sounds like he has plenty of milli-volts.  It's refreshing to see someone who knows how to check pilot voltage BTW.  

If I was more familiar with Honeywell I'd suggest doing a continuity check on the pilot coil, but I can't tell you what that should read.  Perhaps others can help, but in the end it sounds like a sticky valve.

The only reason  suggested jumping the switch is in case the wiring is shorting some where.  A continuity check won't show that.


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## DAKSY (Jan 18, 2009)

The thermocouple puts out 220 mv after 30 seconds and 350 mv after 1 minute.  These seem Ok based on what I'v been able to gather from manual and the internet. 

What!?!!? Your Thermocouple should read about 30 mv MAX..
If you're getting 350 mv, there's something wrong with your t-couple or your meter...
Most t-couples operate between 25-28 mv...
Did you unscrew the threaded end out of the valve, put one multimeter probe on the small silver end & the other one on the copper sheathing to take your reading?


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