Stinky gas pilot light

[wh500special 2,183]

My mother-in-law is selling her house and I’m getting all the little things fixed for her.  Last thing on the list is dealing with her vent-free gas fireplace. 
 

When her house was built about 15 years ago she moved in and has never used the fireplace. It was apparently lit when installed but she shut it off since she didn’t have any desire to use it and didn’t like the smell.  So it’s been sitting. 
 

As many of us are apt to do with our MILs , i dismissed her complaints about the smell as just being hyper critical…oops (sorry Barb!). 
 

Last week I cleaned out the dust and lit the pilot with the piezo push button. Fired right up and the thermocouple heats up keep in the pilot on.  The switch on the wall activates and deactivates the main burner just as it should. 
 

Problem: when the main burner is off and the pilot is burning it stinks up the house with unburned gas smell.   And I don’t mean a subtle odor, it’s strong. 

 

The pilot flame “looks” fine.  It’s blue and doesn’t flicker.  
 

So I shut everything off and cleaned out the little oriface with thin copper wire.  Actually, it’s quite large as these things go.  Blew everything out I could access with air.   Relit. Same thing…give it some time and it stinks the house up. 
 

Called “a guy” the realtor knew.  He came and recleaned everything and said that should do it…it didn’t. 
 

Anyway, I gotta call somebody else who knows what they’re doing to deal with this.  I am guessing an HVAC person can do it.  
 

Question:  what am I watching for when new guy comes?  
 

Before I snuffed it out this last time I stared at it for several minutes.  Just one time I saw a little puff of a flame flash at the oriface where air is sucked into the pilot so it burns clean. That suggested to me that instead of ingesting air into the thing that a little bit of gas is seeping out of there.  Once in a long while it builds up just right to ignite then it goes away. 
 

suggestions are most welcome. 
 

Thanks!

 

Steve

[oliver2-44 9,751]

You might try to find a business that specializes in Gas Fireplaces instead of a HVAC company. Can you find a manufacturer name on the gas fireplace?  If so, contactact them and see who is a dealer in your area. 

[rmaynard 15,459]

Natural gas or propane?

[wh500special 2,183]

Natural gas 

[rmaynard 15,459]

Not that it makes a difference other than the fact that natural gas is lighter than air and propane is heavier. Some suppliers add more "odor" to their gas. My son-in-law installed a ventless natural gas stove in his first house. I could never smell anything, but my wife could. I wouldn't think that it is gas you are smelling since if the pilot is constantly burning, gas if leaking, would be ignited by the pilot. Ventless gas appliances still output methane, O2, and a lot of moisture. I'm not sure that I would have one in my house. Contact a company that specializes in ventless gas appliances and have them check it. 

[SylvanLakeWH 25,559]

Have one. Same issue. Now it's a non-functioning flower stand. Gas shut off. Won't use it for all reasons noted by @rmaynard above.

 

[Pullstart 62,882]

Have you verified the manifold pressure?  Natural should be right around 4” w.c. When running.

[Pullstart 62,882]

Any chance I get to run the ole’ man-o-meter I do!    One time we had a sales rep ask us at the water heater manufacturer if we could send him a new scale for his customer’s roll up u tube manometer.  We asked him if he had a tape measure, that should do just fine.  For a long time, we couldn’t get through his sales driven mind that he doesn’t need a special scale, inches are inches.  

[WHX?? 48,815]

The main gas valve may be leaking by. Might be a leak in the pilot lines too. Even the smallest of leaks can cause a big smell. Soap suds would be your best friend in finding it. 

When I was a HVAC contractor I recommended what we called a hearth dealer. One who deals in gas fireplaces etc. 

I was never a believer on ventless products so my advice is to yank it out.

[wh500special 2,183]

Thanks guys.

 

This is one of those things that came with the house.  I wouldn't select a non-venting gas burner on my own.  I'd rip it out, but that would - presumably - be more work than getting it fixed.

 

My mother in law was a little paranoid to use it and had mentioned the odor.  I dismissed it.  It's hard to quantify odor, but this is very strong when the pilot's been running for any length of time. 

 

There is a mechanical shutoff valve in the wall near the fireplace and then some length of plumbing to the unit itself that's buried.  I left that valve open but the pilot off and didn't detect any odor so I don't think it's a plumbing problem between the valve and the fireplace at least.

 

I didn't measure the gas pressure.  I would guess it is plenty high since the tankless gas water heater isn't starved for gas.  Could be too high I suppose.

 

I've called the nearest dealer for this brand (Monessen) and am awaiting a callback to make an appointment.

 

We'll see.

 

Thanks,

Steve

[lynnmor 7,306]

I never dealt with natural gas but have used propane for years.  I found that the odor is strong just before the propane bottle is empty.  I wonder if the added odorant settles out and causes the excessive smell due to none use.  I would try running the system wide open for some time and see if that might help.  

[squonk 41,118]

Pilot line is quite often soft aluminum tubing with compression fittings. Could be a tiny crack leaking once the gas valve opens the pilot to supply gas. And yes the odorant can settle in the drip leg at the appliance and work it's way out when unit is turned on again.

[Pullstart 62,882]

1 hour ago, lynnmor said:

I never dealt with natural gas but have used propane for years.  I found that the odor is strong just before the propane bottle is empty.  I wonder if the added odorant settles out and causes the excessive smell due to none use.  I would try running the system wide open for some time and see if that might help.  

LP runs 10” w.c. manifold pressure because it’s heavier than air.  Low tank, low pressure, gas doesn’t get through the air gap and to the burner.  Though this is natural gas and it is lighter than air, manifold pressure still matters.  

[oliver2-44 9,751]

Let us know what they find.

[wh500special 2,183]

8 hours ago, lynnmor said:

…I would try running the system wide open for some time and see if that might help.  

I did that a week or so ago.  I Opened all the windows in the house and ran the fireplace for about two hours full blast.  It was about 90 F outside that day so it was quite warm in the family room by the time I shut it down.  It sure made packing up furniture and belongings a lot of fun. 
 

There is no discernible smell when the main burner is rolling. 
 

Unfortunately, it didn’t make any difference in the odor which really seems related juts to the pilot light.  That’s what prompted me to see if I could clean the pilot light after it cooled down again. 
 

The local dealers for these apparently don’t need repair business because they aren’t being responsive to calls left on their voicemail.  I sent an email to one now hoping it’s monitored.  
 

For those keeping score and who are curious, allowable supply pressure is 5-11” and manifold pressure is to be 3.5”.  I have probably 50 pressure meters in this pressure range at work so if I get no response I’ll start hooking up tubing to see what’s what. 
 

I’ll update at the next sign of progress. 
 

Thanks again,

Steve

[WHX?? 48,815]

1 hour ago, wh500special said:

The local dealers for these apparently don’t need repair business because they aren’t being responsive to calls left on their voicemail.  

Odds are not good in your favor. Hard to find help these days. 

Ya know a pic(s) of the setup might help us out alot. 

9 hours ago, squonk said:

Pilot line is quite often soft aluminum tubing with compression fittings. Could be a tiny crack leaking once the gas valve opens the pilot to supply gas. 

Much as it kills me to say the Squonky might be right ... 

 

[WHX?? 48,815]

1 hour ago, wh500special said:

allowable supply pressure is 5-11” and manifold pressure is to be 3.5”.  

Correct ... most if not all natural gas meters are set at 7" and regulated down to 3.5 if the gas valve has a regulator. 2 psi gas systems being the odd ball but then you would see a 2 to 7" regulator in the supply piping. 

Edited August 2, 2023 by WHX??
Speeling

[Tractorhead 9,064]

14 hours ago, wh500special said:

Thanks guys.

 

This is one of those things that came with the house.  I wouldn't select a non-venting gas burner on my own.  I'd rip it out, but that would - presumably - be more work than getting it fixed.

 

My mother in law was a little paranoid to use it and had mentioned the odor.  I dismissed it.  It's hard to quantify odor, but this is very strong when the pilot's been running for any length of time. 

 

There is a mechanical shutoff valve in the wall near the fireplace and then some length of plumbing to the unit itself that's buried.  I left that valve open but the pilot off and didn't detect any odor so I don't think it's a plumbing problem between the valve and the fireplace at least.

 

I didn't measure the gas pressure.  I would guess it is plenty high since the tankless gas water heater isn't starved for gas.  Could be too high I suppose.

 

I've called the nearest dealer for this brand (Monessen) and am awaiting a callback to make an appointment.

 

We'll see.

 

Thanks,

Steve

 

Hi steve,

here unvented fireplaces and Waterheaters without seperate exhaust be vorbidden since more as 15 years.

 

In the day‘s before, they where in some Houses, but after the new Double insulated Windows came up,

the plumbers association here prevent to use the unvented gas- systems.

At my Mil‘s home there is untill today a Waterheater, that they smells even just on pilot flame is normal.

Depending how long they run, the smell goes all arround.

 

if there be other options, i.eg. Electric use them.

a permanent pilot flame is a waste of ressources.

newer systems doesn‘t need a pilot flame, they have electric ignition while start.

 

 

[wh500special 2,183]

Updating.

 

The technician is scheduled for next week.  In talking with the folks that sell and service these things it sounds like potentially that a strong gas smell could be a fact of life, but it's still hard to believe it could smell THIS bad and be acceptable.

 

Steve

[Tractorhead 9,064]

Gas is contaminated with a strong smell for security reasons.

So it will normally stink heavy before it becomes any dangerous,

but this ( the stink) is not a good indication about the quantity of dangerously, because it is too subjective.

 

it is a subjective thing. For some people it smells stronger, others doesn‘t smell it that strong.

 

[wh500special 2,183]

This took an interesting turn. 
 

The buyer of the house had it checked today and was given the all-clear.  So, everything is apparently working as designed and, most importantly, safely.  👍🏻

 

Since they’ve taken the reigns on this it is no longer my problem and I can move on to a few piddly little fixes they’ve identified. 

I’m not particularly sensitive to odors but this seemed excessive to me.  But, it’s in spec so nothing to be fixed. 
 

thanks for the suggestions. 
 

Steve 

[SylvanLakeWH 25,559]

20 minutes ago, wh500special said:

This took an interesting turn. 
 

The buyer of the house had it checked today and was given the all-clear.  So, everything is apparently working as designed and, most importantly, safely.  👍🏻

 

Since they’ve taken the reigns on this it is no longer my problem and I can move on to a few piddly little fixes they’ve identified. 

I’m not particularly sensitive to odors but this seemed excessive to me.  But, it’s in spec so nothing to be fixed. 
 

thanks for the suggestions. 
 

Steve 

 

Just curious, got that in writing from the firm that did the inspection? If that was an identified issue in a real estate transaction I would document all inspection results...

[wh500special 2,183]

Excellent point. 
 

Our realtor is taking care of these details and putting on the selling paperwork. 
 

Steve