Pilot keeps going out in a direct vent fireplace

[New Daddy]

In my livingroom is a Heat-n-Glo direct vent fireplace. It worked fine as late as last winter.

But this winter, the pilot and the burner go out within 30 minutes of ignition on average. The fireplace stayed on for more than 2 hours on just one occasion out of 6 that I've tried.

Some observations that may or may not explain the cause of the problem are (some of them may have existed in previous winters when the fireplace was working fine):

(1) I can feel considerable downward, cold airflow from the vertical vent. I'm assuming it's the combustion air from the outer layer of the coaxial vent. Anyways, the air current is strong enough for you to know something is coming down from above.

(2) When the burner is on, my wife says she can smell gas. There is no smell of gas when only the pilot is on. She says she starts to smell it when the burner goes on.

(3) The pilot can stay on for days, as long as we don't turn on the burner. It goes out, along with the burner flame, only after the burner goes on.

(4) I'm not a professional, so I can't be sure, but there doesn't seem to be any clogging or debris around the pilot. I tried to air gun the pilot with a compressed air can to make sure. That didn't help.

I'm going to call a professional, but if it's something easy to fix, I'd like to do it on my own and save money.

 

[DAKSY]

Which model do you have?
You said vertical vent. There is an adjustable restrictor
plate which is required for vertical vents, & the setting
is determined by the overall height of the vent.
Is the exhaust restrictor plate installed?
What setting is it on?
If it's in there & set to the correct position, re-light the pilot
& turn the unit on.
Watch the pilot. Is it agitated or is it holding steady?
If it's agitated, you will have to try to determine what the path
of the airflow is that's causing the agitation.
Once you know that path, maybe we can help you stop it from happening.

 

[New Daddy]

Which model do you have?
You said vertical vent. There is an adjustable restrictor
plate which is required for vertical vents, & the setting
is determined by the overall height of the vent.
Is the exhaust restrictor plate installed?
What setting is it on?
If it's in there & set to the correct position, re-light the pilot
& turn the unit on.
Watch the pilot. Is it agitated or is it holding steady?
If it's agitated, you will have to try to determine what the path
of the airflow is that's causing the agitation.
Once you know that path, maybe we can help you stop it from happening.

Thanks Bob.

I have SL-550TR-C.

I don't know if there is an adjustable restrictor plate or not. Where am I supposed to find it? The vent is vertical but may or may not have an elbow, if that should matter. Is there any reason to believe that the setting of the exhaust restrictor plate is not correct? The fireplace worked fine last winter, and we haven't done anything to it since.

 

[DAKSY]

Which model do you have?
You said vertical vent. There is an adjustable restrictor
plate which is required for vertical vents, & the setting
is determined by the overall height of the vent.
Is the exhaust restrictor plate installed?
What setting is it on?
If it's in there & set to the correct position, re-light the pilot
& turn the unit on.
Watch the pilot. Is it agitated or is it holding steady?
If it's agitated, you will have to try to determine what the path
of the airflow is that's causing the agitation.
Once you know that path, maybe we can help you stop it from happening.

Thanks Bob.

I have SL-550TR-C.

I don't know if there is an adjustable restrictor plate or not. Where am I supposed to find it?

It will be screwed into the very top of the firebox. There may be a piece of sheet metal covering it,
angled down from front to back. Take a look at your owners/install manual

The vent is vertical but may or may not have an elbow, if that should matter. Is there any reason to believe that the setting of the exhaust restrictor plate is not correct? The fireplace worked fine last winter, and we haven't done anything to it since.

An elbow or two won't matter. If no one has worked on it then the restrictor shouldn't have moved - if it's in there.
Can you see the cap? Is it clear of obstructions? Has anyone been on the roof or has any work been done near the venting?
How's your gas pressure? Is there soot on your glass? Are all the glass clips secure?

 

[jtp10181]

Do you feel the air coming down all the time? Or just when the glass is off?

Sounds to me like the glass might be unclipped. There should be 4 spring loaded clips for the glass, one on each corner.

You should get NO cold draft when the fireplace is not in use, it is an air tight sealed system (the fireplace is anyway, can't speak for your house itself).

Might just need a new thermopile the fix the pilot issues.

For the gas smell... you should NEVER smell gas. So, STOP using the fireplace, call a pro, make sure they find and fix the gas leak!

 

[New Daddy]

It will be screwed into the very top of the firebox. There may be a piece of sheet metal covering it,
angled down from front to back. Take a look at your owners/install manual

An elbow or two won't matter. If no one has worked on it then the restrictor shouldn't have moved - if it's in there.
Can you see the cap? Is it clear of obstructions? Has anyone been on the roof or has any work been done near the venting?
How's your gas pressure? Is there soot on your glass? Are all the glass clips secure?

I don't see any sheet metal directly covering the vent. There is a sheet metal screwed to the top of the box with a faux-brick texture, as you can see in the attached picture. Is that the restrictor plate? The manual has no description of this part, whereas it says "For vertical venting of 20 feet, a restrictor plate is recommended for improved flame appearance."

There is no reason to suspect any obstruction of the cap. The cap is usually visible, but I'll have to check again when this snowstorm stops, hopefully tomorrow. By the way, we had our outside repainted this summer. The repainting didn't require any climing on the roof, but who knows. If there was any obstruction, can you still feel pretty strong downward draft from the vent? Because I feel pretty good downward airflow from the vent, as I mentioned in the OP.

As to the gas pressure, I think it's fine. The pilot comes on pretty strong, and so do the burners, until the go out. There is no soot on the glass, and the glass clips are secure.

Thanks.

 

[DAKSY]

OK. the restrictor - IF it's in there will be above that shiny "Faux Brick" panel INSIDE the fire box.
It'll look like a flat donut, about 8" in diameter with a 3" hole thru it.
Once again, relight the pilot & turn the burner on. Watch the flames.
Do they lift off the burner BEFORE the pilot goes out?
If not, & the pilot goes out first, is the pilot REALLY agitated?
Is it steady on the thermocouple (smaller of the two pilot sensors)?

 

[New Daddy]

OK. the restrictor - IF it's in there will be above that shiny "Faux Brick" panel INSIDE the fire box.
It'll look like a flat donut, about 8" in diameter with a 3" hole thru it.
Once again, relight the pilot & turn the burner on. Watch the flames.
Do they lift off the burner BEFORE the pilot goes out?
If not, & the pilot goes out first, is the pilot REALLY agitated?
Is it steady on the thermocouple (smaller of the two pilot sensors)?

Then there is defintely no restrictor in our fireplace. Attched is a picture that I took of the vent with the camera lying on top of the "faux brick" panel. There is nothing that looks like a flat donut with a hole between the metal panel and the vent, and nothing in the proximal end of the vent either, as can be seen in the picture.

I've been busy clearing the snow, but will try to watch the flames as you instructed.
It's a hit or miss, and the flames can stay on for a couple of hours, so I can easily miss the moment the flames extinguish.
At least while they were on, I noticed no agitation in the pilot.

Thanks.

 

[DAKSY]

I'd say you DEFINITELY need a restrictor in there.
Do you still have the install manual? The restrictor from Heat & Glo
comes in in the plastic bag with the manual.
If not, see if you can find out what company did the install.
They probably have a LOT of em layin around.
They come with every unit, & are not used in horizontal applications...
Your problem comes from the exhaust leaving the firebox too fast.
In order to replace that exhaust, the incoming air comes in just as fast
& it blows the pilot off the thermocouple intermittently, & this causes the
Millivolts to drop below what will keep the gas flowing to the pilot.
When the pilot drops out, the gas to the burner stops as well.

 

[New Daddy]

I'd say you DEFINITELY need a restrictor in there.
Do you still have the install manual? The restrictor from Heat & Glo
comes in in the plastic bag with the manual.
If not, see if you can find out what company did the install.
They probably have a LOT of em layin around.
They come with every unit, & are not used in horizontal applications...
Your problem comes from the exhaust leaving the firebox too fast.
In order to replace that exhaust, the incoming air comes in just as fast
& it blows the pilot off the thermocouple intermittently, & this causes the
Millivolts to drop below what will keep the gas flowing to the pilot.
When the pilot drops out, the gas to the burner stops as well.

Are the parts shown in the attached picture a restrictor plate? I found them in the plastic bag with the manual, but we keep all appliances manuals together, so they could be just as well from the refrigerator, oven, washer or dryer. Unfortunately, they don't match your description and also don't resemble the diagrams of restrictor plates I googled.

If I can obtain a restrictor plate from the dealer, is it easy to install?

My last question is, why would the absence of a restrictor plate all of a sudden cause a problem, when there was no issue without a restrictor plate last winter, and presumably for many winters before that when the house was owned by someone else?

Thanks!

 

[DAKSY]

None of those are the restrictor. Not sure about the two boomerangs, but the square is
a metal junction box cover plate.
The restrictor is held in with one or more zip screws.
All you need is a screw gun with a magnetic tip for the install.
I don't know why the problem started now, it IS unusual.
It just may be time for a pro to come out & run thru a diagnostic
& clean & tune your unit.

 

[jtp10181]

For the gas smell… you should NEVER smell gas. So, STOP using the fireplace, call a pro, make sure they find and fix the gas leak!

 

[New Daddy]

None of those are the restrictor. Not sure about the two boomerangs, but the square is
a metal junction box cover plate.
The restrictor is held in with one or more zip screws.
All you need is a screw gun with a magnetic tip for the install.
I don't know why the problem started now, it IS unusual.
It just may be time for a pro to come out & run thru a diagnostic
& clean & tune your unit.

Thanks!
I've made an appointment with a local fireplace technicial. He seems to be very busy. I wish I had test-run my fireplace earlier.
I'll report back when the technician pins down the problem and fixes it.

 

[ruth140]

you should have your gas fireplace serviced every year. call before the heating season, your local dealer will be less booked and you can avoid any problems.
when your fireplace keeps shutting down its because it is "sensing " a problem and shutting itself off. trying over and over to make it work..will probably not fix the problem

 

[New Daddy]

I'm reporting the result of the visit by a technician.
It turns out that the thermosensor prong that the pilot is supposed to keep heating was a little bent and was not getting exposed to the pilot flame enough during use. So the fireplace was lead to think the flame went out and shut the gas supply. I have no idea what caused the deformation of the prong.
The technician straightened the prong with a plyer, and the fireplace has been working fine since.
A quick, easy fix, but it needed a pro nonetheless.
I'm glad the issue was not something of more significance (and cost).

Thanks for your support everyone.

 

[ruth140]

i love happy endings glad it was a simple fix!

 

[jtp10181]

Its not really possible for the thermopile to be bent, nor have I ever seen the bracket for the pilot twisted in such a way the thermopile was out of line with the pilot. Possibly the pilot hood was bent and not sending the flame at the thermopile correctly.

I hope they addressed the gas leak with an electronic gas detector and verified you do not have a leak.

 

[Wood Heat Stoves]

Its not really possible for the thermopile to be bent, nor have I ever seen the bracket for the pilot twisted in such a way the thermopile was out of line with the pilot. Possibly the pilot hood was bent and not sending the flame at the thermopile correctly.

I hope they addressed the gas leak with an electronic gas detector and verified you do not have a leak.

good point, if the pilot bracket was twisted, the pilot tube could be too

 

[DAKSY]

Its not really possible for the thermopile to be bent, nor have I ever seen the bracket for the pilot twisted in such a way the thermopile was out of line with the pilot. Possibly the pilot hood was bent and not sending the flame at the thermopile correctly.

I hope they addressed the gas leak with an electronic gas detector and verified you do not have a leak.

I'm thinkin that he was talking about the THERMOCOUPLE.
I HAVE seen them bent in an attempt to get more pilot engagement.
In MOST cases it was because the gas line was undersized (NG) & the
volume simply wasn't present at the pilot when another (dryer...waterheater)
appliance was calling for the gas UPSTREAM.
Without adequate volume, there was no pilot adjustment, so the QUICK FIX
was the distortion of the TC...

 

[jtp10181]

Yes probably the TC actually. When I read the first post the other day I thought it said the pilot never went out, but now I read it again and it clearly says the pilot was going out with the burner. Not sure how I missed that the last time I looked at it.