Mystery Gas Leak

[pluffmud]

I have a 2 year old A. O. Smith 40 gallon natural gas water heater located in the garage - professionally installed. Faint smell of natural gas in the garage in the AM that dissipates during the day as the burner comes on and the garage door is used.

Tech came out and found no connection/line leaks from the gas supply to the heater.

Tech coming back tomorrow to get to the bottom of it, At this point I am thinking it is an internal part or a venting issue - did a rudimentary vent test with a lighter and it seems to draw fine.

Has anyone dealt with this particular situation? The techs for this company are good but any input from another source is always helpful. Thanks!

 

[Twowaxhack]

I have a 2 year old A. O. Smith 40 gallon natural gas water heater located in the garage - professionally installed. Faint smell of natural gas in the garage in the AM that dissipates during the day as the burner comes on and the garage door is used.

Tech came out and found no connection/line leaks from the gas supply to the heater.

Tech coming back tomorrow to get to the bottom of it, At this point I am thinking it is an internal part or a venting issue - did a rudimentary vent test with a lighter and it seems to draw fine.

Has anyone dealt with this particular situation? The techs for this company are good but any input from another source is always helpful. Thanks!

Yes, I’ve repaired many gas leaks.

There’s a leak and your plumber needs to find it. It may or may not be the water heater. Could be the piping to the heater.

Use leak detection solution or a thin soap solution to find small leaks.

 

[BlueSkyHigh]

Tech coming back tomorrow to get to the bottom of it, At this point I am thinking it is an internal part or a venting issue

The last water heater I had installed came with a "free" inspection by the local government gas police. They noticed a smell similar to what you are describing. The inspector pointed to an internal connection that was visible after the sight glass was removed and told me to put a wrench "right there" and give it a turn. I asked if he could do it and he said "no" so I got out the wrench and cranked down on the connections/joint. He passed the installation after that.

 

[Geofd]

Check your draft, see if it's pulling out gases properly,if it's only when it firing off you may e getting a pre ignition smell, there are vents on the bottom of the heater are the faced out or not blocked by any thing.

 

[pluffmud]

Thanks for the advice y'all. Tech did a good leak check last week of the connections/lines from the gas supply to the heater with the foaming liquid - no leaks; I was out there with him - I suppose there could still be one in those lines - I'll get him to do it again today.

The gas odor is only noticeable in the AM after the heater has been sitting all night - it's pretty hot down here in the SE USA and the garage is not insulated so I am assuming the burner has little or no need to fire up overnight.

The above has me thinking the pilot supply or other internal gas connection may be leaking just a bit - once the burner fires up during the day the odor dissipates.

The vent seemed to be drawing well when I did a simple vent test with a lighter, but I'll get him to do a proper one today.

Heater only a couple of years old so I hope it's a relatively minor fix. Thanks again!

 

[Twowaxhack]

Use a manometer to determine if you have a leak or not.

If the manometer shows a leak then you can track it down with a combustible gas detector and then pinpoint with soap.

You can also isolate sections of piping and test with the manometer.

The manometer will show small leaks fast.

Gas leak detection equipment will get you in the general area. It’s also so sensitive it’ll pick up pipe dope and other combustibles besides the gas.

Gas control valves and regulators do have an allowable leakage and gas detectors will pick it up.

 

[pluffmud]

Use a manometer to determine if you have a leak or not.

If the manometer shows a leak then you can track it down with a combustible gas detector and then pinpoint with soap.

You can also isolate sections of piping and test with the manometer.

The manometer will show small leaks fast.

Gas leak detection equipment will get you in the general area. It’s also so sensitive it’ll pick up pipe dope and other combustibles besides the gas.

Gas control valves and regulators do have an allowable leakage and gas detectors will pick it up.

Well, that is valuable information - thanks! I did not know there was allowable leakage - hopefully the tech has a manometer and can pinpoint the leak. I'm going to pick one up this weekend to have here at the house as well.

When I get a minute I'm going to read through the forum opinions on tankless gas systems - if I live long enough for this tank to wear out I would rather have a unit hanging on the side of the house outside.

 

[Twowaxhack]

You could let the water heater come up to temp, having a full tank of hot water.

Then before you go to bed turn the gas valve off to the water heater.

Then when you get up the next morning go to the garage and see if you smell gas.

If you don’t then it’s probably the water heater. If you do smell gas then it’s probably in the piping.

You’ll still have a full tank of hot water.

 

[Geofd]

I wonder also if it's in a garage if these enough fresh air,there are codes and calculations,when installing a gas water heater in a closed inroom,my boiler has a door with slats in it so.it takes fresh air from the basement

 

[pluffmud]

I wonder also if it's in a garage if these enough fresh air,there are codes and calculations,when installing a gas water heater in a closed inroom,my boiler has a door with slats in it so.it takes fresh air from the basement

I was wondering about that, too - the heater manual has the formula to calculate minimum air needed - I just went out and checked the fresh air intake vent/filter - fresh air intake runs the circumference of the heater at the bottom and the filter looks clean - I'll have the tech check that as well when he gets here today. No outside air supply to the garage other than what what gets in through the garage door when it is closed.

 

[pluffmud]

You could let the water heater come up to temp, having a full tank of hot water.

Then before you go to bed turn the gas valve off to the water heater.

Then when you get up the next morning go to the garage and see if you smell gas.

If you don’t then it’s probably the water heater. If you do smell gas then it’s probably in the piping.

You’ll still have a full tank of hot water.

That is a plan. Thanks!

 

[pluffmud]

Well, tech found the leak (video) - manifold door gasket; could see the bubbles - prob a 20.00 part. Parts and tank under warranty for 9 years; labor for only 2 and I bought it 1/3/2020. Of course.

Don't think this is a repair I should try myself so I guess I'll have to pony up.

Edit - IDK; watched a couple of tech Youtubes doing the burner replacement - on the face of it looks like I could accomplish that and it would save some $.
View attachment 2e6a48f8-d874-45e5-a04b-8a450d1707ab_cdv_video_001.mp4

 

[Twowaxhack]

I personally do not believe he’s found the leak.

That gasket isn’t the cause of a of a natural gas leak.

That’s the burn chamber gasket that’s part of the FVIR system.

 

[Rickyman]

I personally do not believe he’s found the leak.

That gasket isn’t the cause of a of a natural gas leak.

That’s the burn chamber gasket that’s part of the FVIR system.

I agree, gas leaking in the burner compartment would rise up through the vent not push out that gasket

 

[pluffmud]

Thanks. Well, I tend to agree with both of you - was thinking about it; I am not a professional technician, but basic physics would seem to dictate any excess gas/exhaust would be routed up the vent and not build up to the point it has enough pressure to force its way out through the burner door gasket. Does that make sense to you?

I think I will have A.O. Smith send me a new burner assembly and I will get up on the roof today and see if there is a vent cap issue.

Y'all every run across clogged or inefficient vent caps causing issues? IDK what could be clogging it - guess I'll find out in a few.

 

[Twowaxhack]

Did you turn the gas off to it last night and see if you smelled gas this morning ?

 

[pluffmud]

Did you turn the gas off to it last night and see if you smelled gas this morning ?

No, because I forgot and fell asleep on the couch watching Forensic Files. I'll do that tonight. On the plus side A.O. Smith was pleasant to deal with a few minutes ago - sending a new burner assembly, under warranty. And I'm about to climb up on the roof and check the vent cap.

 

[Twowaxhack]

No, because I forgot and fell asleep on the couch watching Forensic Files. I'll do that tonight. On the plus side A.O. Smith was pleasant to deal with a few minutes ago - sending a new burner assembly, under warranty. And I'm about to climb up on the roof and check the vent cap.

You need to determine if you’re smelling combustion gas or natural gas.

Sounds like everyone’s guessing.

 

[Twowaxhack]

AO Smith has a history.

https://www.cunninghambounds.com/blog/2007/october/-50-million-awarded-in-water-heater-death-case/
Be careful

 

[pluffmud]

You need to determine if you’re smelling combustion gas or natural gas.

Sounds like everyone’s guessing.

That's sure how it feels. I know I am guessing and I don't have many answers after 2 tech visits this week. His manometer did alert to the burner door gasket leak and confirmed with the bubble spray, but as you say, that is just pressure and does not identify the gas. I'll shut down the gas tonight.