NG Gas burning wood stove shutting off

[Tmacmi]

We have an Avalon Prairie gas stove. It is shutting off after approximately 10 seconds of operation. The pilot stays lit while off.

One potential issue is that it has a very short flue. The stove is in the basement. The flue runs up approx 6' then turns 90 degrees, then runs approx 3' to the exterior of the house.

When we first got the house the stove worked fine. Now it doesn't

I presume there is some type of CO2 sensor in there that doesn't like the build up because the short stack can't heat up quickly enough.

However that doesn't necessarily explain why it used to work and doesn't now.

Do you know where the sensor is found? Can the sensitivity be reduced?

 

[DAKSY]

1) NP is not a fuel. NG or LP are. Which one are you burning?
I will correct your title once you let me know.
2) Do you have a multimeter? You need to read the output of your thermopile (TP).
The TP probably needs replacement.
3) CO2 is not a problem. CO is. There is no CO detector in a gas stove.
You need to have CO detectors in the room where the stove is, near bedrooms
& on each floor of your home.

 

[Tmacmi]

Natural Gas. Thank you for changing.

The its showing 557 millivolts when just on pilot and then 285 when main is on (until it just goes out)

I don't know if this as anything to do with it but when the stove is on I can see the thermocouple and the pilot flame doesn't look as consistent. It seems to "dance around" I can't see the thermopile when the stove is on.

 

[DAKSY]

Changed.
Reading is a little high with the burner on.
Can you adjust the pilot down?
Have the logs been moved from the original placement?

 

[Tmacmi]

Thank you.

The pilot is turned up to high to offset the wavering of flame. I'll turn it down and test.

I have taken the logs off to look at the pilot after it started having this problem, but they go back matching on the studs set in the base.

 

[DAKSY]

Are all of the logs held on Studs? Usually, only them lower ones are, & the rest are stacked on them.
If you have one too close to the pilot assembly, it can cause a heat build up on the TP & shut the burner off...

 

[Tmacmi]

There is one log in the back set on studs. There are two smaller logs in front set to each side to replicate a burnt through log.
In any event it appears to be the thermopile regardless. I just went down and measured again after turning down the pilot slightly. It showed 235 millivolts, even when turned back up it hovered at 235 millivolts.

When I turned the fire on it fell to 222 and 218 millivolts on each try respectively before turning off.

 

[DAKSY]

Is the pilot coming off the thermocouple?
You mentioned the flame was wavering.
Does you stove have an air restrictor?
If so, is it set correctly?
Your manual will tell you what the setting
should be for your venting length...

 

[Tmacmi]

The air restrictor is set per the manual.

I checked it again and the thermopile is reading 235 millivolts. From what I've seen elswhere that is considered too low correct?

 

[DAKSY]

The air restrictor is set per the manual.

I checked it again and the thermopile is reading 235 millivolts. From what I've seen elswhere that is considered too low correct?

With the burner on, No.
It's fine at that number.
With only the pilot burning, yes.
Should be around 500mV

 

[Tmacmi]

Thanks. It sounds like I'll be installing a new Thermopile.