Slight gas odor from Lennox furnace

**vtxdude** · 12-13-2009, 09:04 AM

Model # is C26-21-1

I had the cover off of the furnace today and thought I caught a whiff of natural gas...not overpowering and only detectable if I stuck my face right up at a certain place in the furnace..it is not spread to the cellar and doesnt seem to be growing

Take a look at this pic

The smell is coming from the upper right hand corner of the silver box the best I can tell...right to that the right of that top bolt on right...at the very corner(s) of each side of the box next to top bolts there is a small opening into the box...they look like they were built that way

You know maybe it has always been like this and I am just noticing because I have been super wary of smells lately......

Is this something I should be worried about?

**vtxdude** · 12-13-2009, 10:46 AM

I just had National Grid (gas Company) and he used some sort of meter on it...it stayed zero for almost the whole time he checked with it going to 0.05 briefly. He said that there may be something wrong with the gas valve but since he was not a plumber or HVAC guy he could not be sure.

In any event he said that everything checked out fine even with that minuscule reading...he used that meter on every connection he saw in the furnace and in the cellar and it all checked out at either 0 or 0.05

He said if he thought there was any danger he would have shut everything down and red flagged the place

If it is the gas valve is that a difficult and costly repair?

The smell seems to be coming from this opening but this opening has always been here..it looks like it is supposed to be there

Could it be the gas valve is allowing gas to get into burn chamber when it is not supposed to be?

Like I said the gas company guy said the meter is very powerful and if there was a danger it would have picked it up

Thoughts on next step...if I walk by the furnace you don't smell it..if you stick your face inside you get that faint whiff

**vtxdude** · 12-14-2009, 09:03 AM

Does anyone have any ideas?

**Ian Gills** · 12-14-2009, 01:07 PM

It might just be a loose connection somewhere on the gas lines or even on the pilot tube (if you have one). The smell of gas often drifts from where it originates.

He said if he thought there was any danger he would have shut everything down and red flagged the place

You did the right thing and called him out and he would have shut the gas off if there had been any danger. Their equipment is extremely sensitive.

If it is the gas valve is that a difficult and costly repair?

Yes it is difficult and yes it is costly. They rarely fail, especially with the symptoms you are experiencing. I had one fail and I'll tell you about that if you like. I do not think it is that.

This is a tricky one. You could try and call a pro, and have him tighten the connections up. Or just leave it. The risk is that the pro comes out, tinkers and you can still smell the gas.

Have him tighten the connections on the water heater too. Remember what I said about the smell of gas drifting.

Actually, I remember you said you just had a WH installed and had other odor issues with that. Is that correct? If so, I bet it is the connection to that.

**vtxdude** · 12-14-2009, 09:45 PM

The gas company guy said that a hvac guy should have a meter he can attach right to the gas valve and from that he would be able to tell me the pressure and if gas is leaking into the combustion chamber...in other words be able to tell if valve has issues?

**Doherty Plumbing** · 12-14-2009, 10:28 PM

Originally Posted by vtxdude

The gas company guy said that a hvac guy should have a meter he can attach right to the gas valve and from that he would be able to tell me the pressure and if gas is leaking into the combustion chamber...in other words be able to tell if valve has issues?

It's called a manometer and the HVAC guy should have one. They're crucial when adjusting the input to an appliance.