Slight Gas Smell when Steam Boiler Firing Up

NJHomeowner

Hello,

I have a Weil McLain boiler that was installed back in 2015.  I was in my boiler room and noticed a slight gas smell with it first fired up.  It’s similar to when you turn on your stove.

is this normal or do I need to get this checked?  The smell is gone quickly after.

ChrisJ

NJHomeowner said:

Hello,

I have a Weil McLain boiler that was installed back in 2015.  I was in my boiler room and noticed a slight gas smell with it first fired up.  It’s similar to when you turn on your stove.

is this normal or do I need to get this checked?  The smell is gone quickly after.

Most likely normal from your description.
When it first fires there's very little if any draft.

I assume this is an atmospheric vent boiler? Can you share some pictures so we can confirm?

NJHomeowner

Thanks.  I do, it vents through my chimney.

ethicalpaul

What a nice installation. Ezzy, Johnny, or Dave I wonder?

NJHomeowner

It was done by Dave

ethicalpaul

We certainly miss him in North Jersey!

NJHomeowner

Is he ok?  Also any concerns on the gas smell?

ethicalpaul

He's fine last I heard, he's just working for PSE&G now and I'm sure his blood pressure is greatly lowered not being a small business owner anymore LOL

I wouldn't be concerned if it's just momentary like that. Strangely mine never makes that smell--I would actually expect it to once in a while.

I'd have a decent CO detector above the boiler just because it's super cheap and nice insurance.

ChrisJ

ethicalpaul said:

He's fine last I heard, he's just working for PSE&G now and I'm sure his blood pressure is greatly lowered not being a small business owner anymore LOL

I wouldn't be concerned if it's just momentary like that. Strangely mine never makes that smell--I would actually expect it to once in a while.

I'd have a decent CO detector above the boiler just because it's super cheap and nice insurance.

Spending a lot more time near mine lately I have caught a wiff a few times.
It's literally just a hint of mercaptan which is so easy to smell.

I almost typed marzipan.

NJHomeowner

Nice!

Thanks, I have one in the room about 10 feet from it

EBEBRATT-Ed

@NJHomeowner

If it is lighting smooth it is probably ok. If it lights with a rough snap like roll out than have it checked

Hap_Hazzard

I smell a whiff of gas too if I'm standing in the boiler room when it comes on. I tried fussing with the pilot to see if I could make the burners light quicker, but nothing seemed to help.

ethicalpaul said:

Strangely mine never makes that smell--I would actually expect it to once in a while.


That is surprising since you don't have a standing pilot. Wouldn't you think a standing pilot would light the burners quicker than that sparky thing?

ethicalpaul said:

I'd have a decent CO detector above the boiler just because it's super cheap and nice insurance.

Last time I had a flue gas analysis, CO was 0 ppm. I could almost do without the flue, let alone the CO detector.

ethicalpaul

That is surprising since you don't have a standing pilot. Wouldn't you think a standing pilot would light the burners quicker than that sparky thing?

Well the sparky thing only lights the pilot, which then lights the burners so probably not a big difference there.

Hap_Hazzard

ethicalpaul said:

Well the sparky thing only lights the pilot, which then lights the burners so probably not a big difference there.

But still, the gas starts coming out of the pilot before it gets lit. It may be a smaller amount, but it would be in addition to the gas from the burners before they light.

ChrisJ

Hap_Hazzard said:

ethicalpaul said:

Well the sparky thing only lights the pilot, which then lights the burners so probably not a big difference there.

But still, the gas starts coming out of the pilot before it gets lit. It may be a smaller amount, but it would be in addition to the gas from the burners before they light.

It starts sparking before it turns gas on to the pilot, then once that's lit it turns on the main burners which light just as they do with a standing pilot.

They do everything they can to avoid the possibility of a delayed ignition.

dabrakeman

I have an EG65 installed same time period (2014). Noticed same thing since day 1 but it has not changed or gotten worse. Only smell it in the near vicinity of the boiler. Thought maybe the auto flue damper just was keeping the chimney a bit cooler so less initial draft. Nothing close to a rollout so didn't worry about it.

Hap_Hazzard

ChrisJ said:

It starts sparking before it turns gas on to the pilot, then once that's lit it turns on the main burners which light just as they do with a standing pilot.

They do everything they can to avoid the possibility of a delayed ignition.

I'm sure they do, but it's not perfect. I mean, I light my pilot once in the fall and it stays lit all winter, so, all things considered, an electronic ignition must cause more gas to escape, even if only a slight amount. I don't see how it could allow less.

Come to think of it, I'm not sure how comfortable I am with the idea of electronic ignitions. If there's even the smallest leak in your gas plumbing, you could build up a sizeable cloud before you get a spark or open flame to set it off, and a gas explosion can ruin your whole day. I can see where they might be a little more efficient, but safer? I don't think so.

ChrisJ

Hap_Hazzard said:

ChrisJ said:

It starts sparking before it turns gas on to the pilot, then once that's lit it turns on the main burners which light just as they do with a standing pilot.

They do everything they can to avoid the possibility of a delayed ignition.

I'm sure they do, but it's not perfect. I mean, I light my pilot once in the fall and it stays lit all winter, so, all things considered, an electronic ignition must cause more gas to escape, even if only a slight amount. I don't see how it could allow less.

Come to think of it, I'm not sure how comfortable I am with the idea of electronic ignitions. If there's even the smallest leak in your gas plumbing, you could build up a sizeable cloud before you get a spark or open flame to set it off, and a gas explosion can ruin your whole day. I can see where they might be a little more efficient, but safer? I don't think so.

No idea.

I preferred a pilot light on a kitchen stove as it seemed much more reliable.
But, with the huge push for "efficiency" on everything regardless of how practical it is, this is where we're at.

A pilot light generally had a thermocouple that could fail over a long time, maybe the orifice would get a little dirty.

Electronic ignition has all kinds of fun stuff that can cause problems and it costs a small fortune to buy and replace. Everyone always talks about how much a pilot light costs to run but no one discusses what it costs to use electronic ignition. The total cost, start to finish including replacement modules, troubleshooting labor costs etc.

My dad used to let the pilot light on his furnace run 24/7 365 days a year. I think he probably lit it a total of 2 or 3 times in the 28 years he owned that house. He felt turning it off in the summer was asking for issues, so he just let it run. Apparently the cost of gas usage wasn't enough for him to care.

Hap_Hazzard

I've replaced the thermocouple twice. I'm surprised they last as long as they do being red-hot all the time.

I light the pilot every year, but it takes a few minutes to purge the air from the line. This tells me there must be a slow leak somewhere, but even with a gas detector, I've never been able to find it.

When I light it, I hold the lighter under the thermocouple to pre-heat it while I'm waiting for the gas to get there so I don't have to wait another minute for the pilot to heat it up after the gas comes on.

JUGHNE

IMO, the electronic ignition is safer in that if you have flame failure with the main gas valve energized, the system responds within about 2 seconds to drop out power.

The old school T-couples can take well over 30 seconds to shut down all gas.

That is a long time to listen to the main gas flowing waiting for shut down when testing the T-couple safety.

I had a NG 960,000 BTUH boiler from 1963, with 4 pilots/T-couples, which took almost 90 seconds to shut down the main gas valve. The longest counting I ever had.....and to think that originally it was Propane....and is still in a nursing home.

ChrisJ

JUGHNE said:

IMO, the electronic ignition is safer in that if you have flame failure with the main gas valve energized, the system responds within about 2 seconds to drop out power.

The old school T-couples can take well over 30 seconds to shut down all gas.

That is a long time to listen to the main gas flowing waiting for shut down when testing the T-couple safety.

I had a NG 960,000 BTUH boiler from 1963, with 4 pilots/T-couples, which took almost 90 seconds to shut down the main gas valve. The longest counting I ever had.....and to think that originally it was Propane....and is still in a nursing home.

Under what conditions would the main burner and all 4 pilots blow out?

JUGHNE

Dirty burners, delayed ignition of the main burners, plugged heat exchanger, down draft on venting, any number of situations.

I may be over concerned about these things as the last person to touch it ends up owning it for some time.

The 4 pilots are in series, if any one of them fail then the T-couple circuit system opens after the time delay.

This is a pretty scary boiler room, 2 commercial water heaters and mop sink are crammed into this room along with the boiler. A 60 gallon compression is in the attic above the boiler.
There is a large kitchen exhaust hood just down the hall from this. The door is "usually" closed.

There is a huge combustion air inlet that can lead to frozen pipes, I and also the Fire Marshall have found this opening closed in the winter and we both have stated warnings of the dangers.

Of course, as the FM has power to shut the facility down, his warnings are heeded much more than mine.
But a variety of maintenance people cobble jack these things up. FM might show up once a year not necessarily in the winter time.

We completely cleaned the boiler in 2016, was last called to check controls/safeties in 2019.

So it has all the making of the "perfect storm".

I haven't been there for years so may not "own" it anymore.

ChrisJ

JUGHNE said:

Dirty burners, delayed ignition of the main burners, plugged heat exchanger, down draft on venting, any number of situations.

I may be over concerned about these things as the last person to touch it ends up owning it for some time.

The 4 pilots are in series, if any one of them fail then the T-couple circuit system opens after the time delay.

This is a pretty scary boiler room, 2 commercial water heaters and mop sink are crammed into this room along with the boiler. A 60 gallon compression is in the attic above the boiler.
There is a large kitchen exhaust hood just down the hall from this. The door is "usually" closed.

There is a huge combustion air inlet that can lead to frozen pipes, I and also the Fire Marshall have found this opening closed in the winter and we both have stated warnings of the dangers.

Of course, as the FM has power to shut the facility down, his warnings are heeded much more than mine.
But a variety of maintenance people cobble jack these things up. FM might show up once a year not necessarily in the winter time.

We completely cleaned the boiler in 2016, was last called to check controls/safeties in 2019.

So it has all the making of the "perfect storm".

I haven't been there for years so may not "own" it anymore.

It's been going for 60 years so far.