Odour of Gas Furnace

[Gilbey]

We have a Lennox Elite series high efficiency gas furnace. It was installed about ten years ago and is serviced annually. A couple of years ago, it gave some problems and we had the pressure switch, venter motor and motherboard replaced.

From time to time, when the furnace is not actually running, if I go into the furnace room, I detect a very faint odour of natural gas. I asked the service technician if this is normal. He said there will always be a slight odour of gas around a gas furnace.

The gas pipes and the air intake and exhaust pipes all run through the back of the garage - this was the only way to install them, as we have no chimney (House was originally heated by baseboard heaters and then an electric furnace before we installed the gas furnace.) I occasionally smell a faint odour of natural gas in the garage during the heating season.

Should I be smelling any gas at all, either in the furnace room or in the * Many thanks for any advice you can provide.

[Freon]

The best thing you can do is get some very soapy water (you can use spray cleaner like 409) and apply it to each and every connection in the gas system... threaded connections, compression connections, unions... the works. Then look for bubbles. You should not have any gas leaking. So if you see bubbles, I would call someone or you can try and fix it yourself after turning the gas off at the meter. Do every connection right up to the gas valve at the furnace.

The fact this is a new odor (since the vent motor work you had done) and you have had no work done on the gas piping makes me wonder if it is a gas smell and maybe not the funky smell from the condensate of the furnace. Check the condensate drain line trap and make sure it has water.

[how]

Hey Gilbey
If you smell natural gas around your furnace then it needs to be investigated....But
The first question I end up asking clients who they say they smell "natural gas" is "what does it smell like". Rotten eggs is the answer I'm usually waiting for but I can't tell you how many other smells get blamed on a furnace. The most common alternative cause for a smell like natural gas is a dead rodent. If Freons excellent DIY advice for tracking down a gas leak or a dry condensate trap doesn't show anything up, check for something taking a dirt nap in the area.
Note . Women typically notice the smell of mercaptan in the natural gas at 1/2 the concentration that men do so perhaps the wife's nose could be employed.

[Gilbey]

Thanks for the responses. I will see about getting this checked out right away.
I don't think it is water collecting anywhere. The condensate is pumped out and I regularly check the amount coming out by putting a bucket under the tubing where it comes out into the laundry sink.

I have checked for dead rodents and am 100% sure there are none. I am the wife, by the way, so it is my nose that catches the smell. Our gas company sends out a scratch and sniff card several times a year so that we know what the gas smells like.

Thanks again for the advice. This site has been very helpful, this time and in the past.