# Odd problem with gas log fireplace inserts



## dougp26364 (Jan 2, 2008)

When we built our home, I decided to plump the fireplaces for gas starters and then decided to use gas logs rather than real wood. After nine years of no problems I've suddenly developed an issue with the most frequently used set in the basement. 

Every time I light the gas to the set in the basement, the battery operated fire alarms go off in our house. The monitored fire/break in alarm does not sound, just the battery operated alarms and every one of those (three total) go off at the same time. 

At first I thought I just needed to clean the logs off so I washed them off, let them dry and tried it again. Same result of the fire alarms going off. 

So I took the logs out and lit the gas burner. No problem, the alarms did not go off. So I'd say it must have something to do with the logs which are now 9 years old. 

These are the first gas log inserts we've ever had and, to be honest, we don't really use them all that much. I suspected that my step-son, who's room was in the basement, use to light them without telling us (gas bill was unexplainably high at times) but other than that we've only lit them 10 or 12 times per year. 

There is no smoke in the house when the alarms go off and, they stop going off within 5 minutes of me shutting off the flames. To me this is a very odd situation. There is a slight smell of gas when I initially light the flames and again when I shut them off but nothing I hadn't ever noticed in the past and nothing I was not accustomed to with my parents gas log inserts (they lit them about as infrequently as I do). 

Any suggestions before I toss these gas log inserts and spend the money on a new set?


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## wackymother (Jan 2, 2008)

It's your smoke alarms going off, not your carbon monoxide detectors going off, right? 

It's weird that they're all going off simultaneously. Are they on different floors of the house? They're all at different distances from the gas logs?


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## brucenecho (Jan 2, 2008)

Check to make sure your damper is open. Then do a smoke test. To do that roll a bit of paper, then light the log set then light the paper then blow out the flame. With the paper smoking hold it near the top of fireplace opening. If the smoke does not go up the chimney then you properly have a nest of some sort in the flue. Your logs are not at fault.


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## wackymother (Jan 3, 2008)

Are the logs vented or non-vented?


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## Nancy (Jan 3, 2008)

*Replaced logs*

We use our gas fireplace stove all the time.  A couple of years ago we decided to replace the logs and did.  We did not have any problems, just decided it was time.  We've had ours 12 years or longer.

Nancy


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## dougp26364 (Jan 3, 2008)

wackymother said:


> It's your smoke alarms going off, not your carbon monoxide detectors going off, right?
> 
> It's weird that they're all going off simultaneously. Are they on different floors of the house? They're all at different distances from the gas logs?



The three alarms that go off are the smoke detectors. The carbon monoxide detector I have did not go off. All the smoke detectors are on the ceilings in different area's of the house, on two different floors and are battery operated. The carbon monoxide detector is on next to our bedroom and plugged into an outlet along the floor (recommended site by manufactorer). I also have two smoke/heat detectors hardwired/installed by the alarm company when the house was built and neigther of them went off even though both of them are right next to the battery operated smoke detectors.



brucenecho said:


> Check to make sure your damper is open. Then do a smoke test. To do that roll a bit of paper, then light the log set then light the paper then blow out the flame. With the paper smoking hold it near the top of fireplace opening. If the smoke does not go up the chimney then you properly have a nest of some sort in the flue. Your logs are not at fault.



The damper was open. I have looked up the chimney and see daylight out the top. I'm relatively certain it's not the chimney but will give it the smoke test just the same. We have never seen smoke come off a gas burning fireplace with log inserts. The smoke detectors also don't go off when the logs are removed and only the gas flames are turned on. 



wackymother said:


> Are the logs vented or non-vented?



I'm not certain what you mean. I didn't know there was a difference between ceramic fireplace logs. Could you explain the difference between vented and non-vented logs?


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## wackymother (Jan 3, 2008)

dougp26364 said:


> The three alarms that go off are the smoke detectors. The carbon monoxide detector I have did not go off. All the smoke detectors are on the ceilings in different area's of the house, on two different floors and are battery operated. The carbon monoxide detector is on next to our bedroom and plugged into an outlet along the floor (recommended site by manufactorer). I also have two smoke/heat detectors hardwired/installed by the alarm company when the house was built and neigther of them went off even though both of them are right next to the battery operated smoke detectors.
> 
> 
> I'm not certain what you mean. I didn't know there was a difference between ceramic fireplace logs. Could you explain the difference between vented and non-vented logs?



How weird that the hardwired smoke alarms didn't go off and the others did. How about calling the alarm company and discussing that with them? They might come out and do an inspection if you tell them that THREE freestanding smoke alarms went off when theirs didn't. The service tech might be able to shed some light on the whole thing. I guess you checked the batteries on the freestanding alarms, although I can't imagine how that could be involved.

Regarding venting--some gas logs don't need to be vented out. The unit is self-contained. You can put these logs in a pre-existing fireplace and seal off the flue because no venting is needed. (You see these in timeshares a lot--the "fireplace" can look almost like a picture hanging on the wall because there's no need for a real chimney.) 

Other gas logs are meant to be vented to the outside of the house, sometimes through a chimney, or sometimes right through an exterior wall. 

The idea that your flue is blocked makes sense if you have vented logs...except there's not supposed to be any SMOKE coming off gas logs.  

I just remembered there was somebody on the boards who has or had a chimney company. Was it Rick and Cindy? Rick is a firefighter, isn't he? Maybe you could PM them.


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## Wonka (Jan 3, 2008)

I had a similar problem last night.  I started a synthetic log fire (the kind you light that burns a couple of hours).  The fireplace vent was open.  A short time later, one of the alarms started beeping in a back bedroom close to the fireplace.  The funny thing is on the other side of the door (less than 3 feet away) is another smoke detector (closer to the fireplace). It didn't make a sound. It wasn't a steady beep, so I thought it was the battery.  I tried replacing it with three different batteries.  It continued to beep about twice a minute.  I tried everything and finally decided to replace the smoke detector.  Of course, it's not locally available, so I'm waiting for a replacement to be delivered.  When I downloaded the manual on the smoke detectors, they had a reset procedure because they are wired somehow  in unison.  It also didn't work.  One more note.  In our former home, one of the smoke detectors exploded in the middle of the night.  We determined it was caused by using an Alkaline battery after calling the manufacturer.  I also noticed that our current detector's call for a very specific battery.  I do hope you solve your problem.  I had to disconnect the detector until I can replace it.  The beep drives my Yellow Lab crazy...me too!


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## wackymother (Jan 3, 2008)

I just read somewhere that smoke detectors are supposed to be replaced every six years. Did anybody else read that? Meanwhile, mine are at least eight years old, uh oh, gotta get on that. 

If you put all three in at the same time, maybe they're all wearing out simultaneously?


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## rickandcindy23 (Jan 4, 2008)

Wackymother, yes it is the two of us that have a chimney cleaning company and Rick is a Denver firefighter of 33 years (and not retired yet because he is only 52).   

I was reading this and trying to think of what could cause the smoke that would set off a smoke alarm.  Washing logs doesn't seem like it would help at all.  It is unusual for gas logs to set off smoke detectors, usually they don't smoke, but airflow from a furnace is often the culprit for a smoking fireplace.  The furnace is pulling air as it runs and will often pull air right down from the chimney.  If you furnace air intake vents are near a ceiling, this could be why your smoke alarms are going off but you cannot really smell smoke.  The smoke is possibly being pulled by the air intake of the furnace.  

It is just a theory, and I am not confident that is the problem at all, but many fireplace owners complain about sudden smoking when it never has happened before.  A new furnace will pull more air than an older one.  Sealing a house tight with caulking, storm doors or efficient windows can also cause problems you might never have had in the past, too, simply because an airtight house does not provide enough air for a fireplace to burn correctly.  Try opening a window near the fireplace, just a tiny crack, and see if the problem stops.  Then try turning off the furnace and see if that stops the problem.  

Another thing that might be happening, with this cold weather we are having all over the country.   Perhaps the chimney is just too cold to carry warm air up.  Sometimes the chimney is so full of cold air that the fireplace just cannot warm it fast enough. 

I think it is odd that the carbon monoxide detectors aren't going off.   That concerns me because those detectors DO wear out.  They usually start beeping for no reason, which means it is time to replace them.  We buy new ones every three years and have them in three different places in our house.  Rick has seen too many people poisoned by their own furnaces.  SCARY.  

If you cannot figure out the problem, call a gas expert (Rick is not a plumber so he doesn't pretend to know what is wrong with a gas log set).  A licensed plumber or heating contractor can figure out what is going on.  I doubt that your chimney is blocked, but you can check yourself by looking up your chimney in the daylight with a hand mirror and flashlight.


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## dougp26364 (Jan 4, 2008)

wackymother said:


> .........
> Regarding venting--some gas logs don't need to be vented out. The unit is self-contained. You can put these logs in a pre-existing fireplace and seal off the flue because no venting is needed. (You see these in timeshares a lot--the "fireplace" can look almost like a picture hanging on the wall because there's no need for a real chimney.)
> 
> Other gas logs are meant to be vented to the outside of the house, sometimes through a chimney, or sometimes right through an exterior wall.
> ...




Then these are vented gas logs. I can see no blockage in the flu at this times. There is no smoke but there has always been a slight gas smell when lighting the logs and after I put them out. I have checked for gas leaks in the plumbing and there are no detectable leaks.


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## dougp26364 (Jan 4, 2008)

rickandcindy23 said:


> Wackymother, yes it is the two of us that have a chimney cleaning company and Rick is a Denver firefighter of 33 years (and not retired yet because he is only 52).
> 
> I was reading this and trying to think of what could cause the smoke that would set off a smoke alarm.  Washing logs doesn't seem like it would help at all.  It is unusual for gas logs to set off smoke detectors, usually they don't smoke, but airflow from a furnace is often the culprit for a smoking fireplace.  The furnace is pulling air as it runs and will often pull air right down from the chimney.  If you furnace air intake vents are near a ceiling, this could be why your smoke alarms are going off but you cannot really smell smoke.  The smoke is possibly being pulled by the air intake of the furnace.
> 
> ...



The carbon monoxide detector is relatively new. I hadn't thought about the furnace venting but, there is no smoke that can be seen with the naked eye. I've seen our kids burn things in the kitchen and it takes the same smoke detectors a while to go off with visable smoke. 

What I find odd is that they go off ONLY when the logs are in the fireplace. When I remove the logs and light the gas burner up, nothing happens. It doesn't matter how long I leave the flames burning, the detectors don't go off. 

I have a second set of logs in the upstairs fireplace. I guess what I need to to is light that fireplace and see what happens. If the smoke detectors don't go off from the upstairs fireplace then I'll take them downstairs, put them in that fireplace and light it to see what happens. 

Unfortunately I've started a run of 4 nights on, 1 night off and 4 nights on with all shifts being 12 hour nights. It's might be a little while before I can do this experiment.


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## rickandcindy23 (Jan 4, 2008)

Doug, there are certain ways that logs need to be set into the unit to keep the flame from being suffocated.  Make sure the logs are set according to the directions and not just put in there the way you think they look best.  

In all of these years of owning a chimney cleaning business, 25 years, we have never had anyone call with this particular problem.  Maybe a person who installs gas logs would know more than I.  

You might call a fireplace store and tell them what is going on.  We always recommend Lehrer's Fireplace here in Denver because they just know what they are doing and they have been in business 60 years.  But there has to be a company near you that has that same experience.  

The gases from a gas fireplace would probably hit that smoke alarm differently than visible smoke.  The chemicals are what the smoke alarm is reacting to (according to Rick who is sitting right here beside me).  "Smoke alarms do wear out", he is telling me.  Rick works for Denver and people call all the time when their smoke alarms go off for no apparent reason. They bring in new smoke alarms, take the old ones out, and the new ones don't go off.  This is a service that the city provides to its citizens.  Good thing everyone doesn't know about it.  

Carbon monoxide detectors are important to have in or near the room where a gas appliance is located.  Some people only put them near the furnace.  That certainly isn't good enough when you have other gas-burning appliances.


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## shorts (Jan 4, 2008)

This is really a puzzling problem.  My MIL just built a new house and had ventless gas logs installed.  Every time she tries to use the fireplace, her smoke detectors also go off.  She has not called anyone to look at the problem yet - not sure who to call. She has just stopped using the fireplace.  

We suggested she call her contractor but she had so many other problems with the house that she thinks he is getting tired of her calls.  Kinda sad when something brand new doesn't work correctly.


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## Sleepdoc90 (Jan 7, 2014)

*Gas fireplace setting off smoke alarms*

I woke up to fire alarms due to my gas fireplaces. Battery operated all went off. Alarm fire detector did not. Co2 alarm did not go off. I have he'd this happen about 7-8 times since we bought house 14 years ago. We use fireplaces frequently in winter and I have noticed it happens when it is very windy or cold. The wind blows fire into room which I guess makes sense and I guess extreme cold traps exhaust in lower chimney and comes back in room but I can't figure out what they are detecting. I wonder is dust is being ignited as it is blown back into room. Very scary for kids and animals. I just worry that something could be burning in walls. Any more thoughts?  How to prevent?


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## BJRSanDiego (Jan 7, 2014)

*simultaneous alarms*

Our house is wired so that if one detector goes off, they all will.   So you might just have a very sensitive detector.  

Smoke detectors do get old and need to be replaced. 

When changing the batteries (at least annually or better yet,  bi-annually), it is a good idea to vacuum or use pressurized air to blow out the detector.  The canned air works, but will set off the alarm if you energize it within a minute or two.  The propellant apparently has some solvent or gas that sets off the detector momentarily.


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## MuranoJo (Jan 7, 2014)

wackymother said:


> It's your smoke alarms going off, not your carbon monoxide detectors going off, right?
> 
> It's weird that they're all going off simultaneously. Are they on different floors of the house? They're all at different distances from the gas logs?



Sounds like this isn't the OP's issue, but here's another carbon monoxide detector story.

I was cleaning our master bath enclosed shower and suddenly what we thought was a smoke detector in the hallway fairly close by went off.  While I continued to clean, DH was trying to figure out what was wrong as he had replaced batteries and eventually disconnected the smoke detector.  His brother popped by and then started to help him troubleshoot.  Beeping continued.  Our shorthair dog also goes crazy with alarm beeping and desperately wants out.  

Finally, BIL figured it was coming from the carbon monoxide alarm which was very close, but near the floor...and the Clorox cleaner I was using in the shower was causing it.  (I now only use a steam cleaner, but that tells us something about those harsh cleansers.)


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## Roger830 (Jan 8, 2014)

We have electric heat supplemented by a gas fireplace and a gas space heater in the kitchen. Neither are vented and the alarms never went off. The space heater shut down once when it detected low oxygen. 

Our logs are heavy like they might be made from cement.

Like an earlier poster stated, the open flu might be drawing smoke into the house. Try using the fireplace with the vent closed.


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## Carta (Jan 8, 2014)

When this happens, call 911 immediately...Do not take a chance.....Firemen will come in and check...free of charge..(at least where I live)

Just tell them "no sirens needed"


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