Pilot Turbulence

I have an Avalon Ceder free standing direct vent NG stove. It has a standing pilot. Problem is the pilot lights fine, stays running fine, looks perfect. When I turn the burner on, I get pilot turbulence near the thermocouple. The pilot flame continues to engulf the thermopile fine, and the burner pilot is also fine. This turbulence near the thermocouple is eventually enough to shut things down. The stove vent restrictor set to factory spec at position 5 (where it has always been). Air shutter on burner tube is adjusted for proper flame height and color. New pilot, new thermopile, new pilot tube and new thermocouple all installed and everything cleaned. I have tried giving the pilot more gas but It still does it. Also this is not wind related.
Any help would be appreciated!

DAKSY said:

Not familiar with your unit, but it sounds like you need an INTAKE air restrictor. Some units have this adjustment & if you have a tall vertical vent it is almost mandatory. If there isn't one on your unit, sometimes a small piece of aluminum sheet, cut to the height & width of the pilot assembly,can be placed between the pilot & the direction the incoming air is coming from. This can mitigate pilot flame agitation...

Click to expand...

Thanks for your reply. It's strange that this is a recent problem and I am wondering what changed in the system. I do have an intake restictor and like I said, it has always been set to the factory recommended position. I could try closing it one more notch to see if it helps. If it doesnt I would do as you suggest and add some shield over the pilot assy. But before I mess with the original design I wanted to hear from folks on here to see if they ever had such an issue.

wooduser said:

https://www.avalonfirestyles.com/travisdocs/93508117.pdf

Above is the installation and operating manual for your fireplace.

It might be useful to describe in detail how your vent pipe is installed.

Why were all the parts for the pilot replaced, and who replaced them for you? Was that related to this present issue? Di the problem occur before these parts were replaced, or after?

Personally, I would step up the restrictor setting as a test to see if that improves things. Go up several notches if need be to see if an improvement is created.

Describe in detail the appearance of the pilot flame before it goes out. Is it blown around, like a candle flame? Does it change color? Is it blown away from the thermocouple/pilot generator?

A good pilot flame should be like a small blowtorch ---- a sharp blue flame that is resistant to being blown around ----or out. Any sign of yellow tips in the pilot burner flame?

Even a new pilot burner and pilot orifice can be dirty and require cleaning again if it needs it.

Click to expand...

Thanks for responding and good questions!

I have the manual, thanks!

The dual wall vent pipe goes vertical from the stove 3 ft., then at 45 deg. for 1.5 ft, then vertical again for 1.5 ft to ceiling. The vertical section through the ceiling to termination above the roofline is approximately 6 feet. According to the manual, I should have the vent restrictor in position #5 which it has been since install in 2005.

When I started having this issue my first inclination was to clean the pilot assembly since it really has not ever been serviced. It has always run fine. I am very familiar with all the components so I disassembled the thermocouple and it was frozen to the mounting nut resulting in twisted feed line. The pilot line was also frozen in place up inside the orifice, and the end ferrule snapped off. I decided to replace the entire SIT pilot assembly at that point.

The problem occured before and after these changes, so no affect with the new pilot assambly.

I will try changing the restictor setting to see if there is improvement. I was not initially inclined to do this, as the setting was factory recommended based on the vent configuration noted above.

The pilot is blue (like a small blowtorch) and stable. It envelopes the thermocouple and thermopile as it should. When the burner goes on, the flame directed at the thermocouple is noticeably disturbed and is still mostly blue with a yellow tip at the very end of the flame. The swirling action in and around the thermocouple flame is enough to shut it down. The flames directed at the thermopile and burner are unchanged - perfect.

Of note: The rear log has a square cutout which provides clearance for the pilot assembly. As an experiment, I removed the rear log and let the stove run for 36 hours. There were NO issues with the pilot with this log removed. The problem goes away. So this can be a further clue in this mystery. Today I have replaced the log but changed the restrictor setting to position #3. I will post with results.

I hope this info is helpful.

wooduser said:

Thanks for the additional details.



This supports the idea that the issue is with some kind of turbulence caused by the log.

However, most gas fireplace issues are caused by dirty pilot orifices, and even new ones can be no good. If it were me I'd change out the pilot orifice again, based on those probabilities and the yellow tipping. It shouldn't be as much of an adventure as the last time!

You apparently have everything else set up the way the manufacturer specifies. With a good installation, it should work and if it doesn't it should be because of a defective part. The part that creates MOST issues with gas fireplaces is the pilot orifice.

So it's the most likely thing to correct the problem, with the additional benefit of being a cheap part and easy to replace, your previous experience notwithstanding.

Click to expand...

I have been running for two days now without the issue. It appears that opening the vent restrictor a couple of notches did the trick. I think the turbulence near the pilot was the result of inadequate draft. Thanks again for all the responses.