Triangle Tube Propane Smell - Need Ideas - Please help!

smithfan

So, long story short. We have a Solo 110 Boiler that fills our basement with a propane smell usually on the coldest days of winter, sometimes runs and NO smell at all. Last May I had someone out here to look at it because it was piped wrong and setup wrong. At that time they did the re-piping and also used their machine to get the gas/air mix exactly to specs. We also checked for leaks and didn't find any. I assumed the gas/air mix was off so it would be fixed, but here I am again with this smell.
I took the cover off so I could identify where the smell was coming from, and it seems to be coming from this pvc vent inside that the manual has labeled NTC Sensor. At this point I'm am completely beside myself why this is happening and would greatly appreciate any and all ideas this great forum could offer.

kcopp

What does the vent piping outside look like?
It could be when the boiler is in low fire you get cross contamination/ reversion....
That would be the exhaust is being sucked back I the intake.

smithfan

I'll take a picture of the venting tomorrow when it's light out. However, based on manual it looks textbook.

Rich_49

Wind can make textbooks not make sense . Check the location in the textbook and if it is near an inside corner or if something is blocking the exhaust . Wind blowing across the 2 just so can bring exhaust right into the intake's path .

kcopp

I am going to guess right now it is a Concentric vent termination.... NOT a fan of these....aka they suck. Literally.
I have seen way too many issues w/ cross contamination.

Zman

A gas valve that is not closing completely would probably give you a propane smell in that location. Is it more noticeable when the boiler is running or off.

SWEI

Are you experiencing rough ignitions (whuump!) as well? There is a service bulletin for these -- you have the MCBA control which may be affected.

Tom_133

By chance does it fog horn at all? The venturi's go bad quite often with cross contamination or just over time the plastic gets brittle.

smithfan

It's only when the boiler is running. It's been really bad these last few days. As far as the "Whummp" sound, I do get that on ignitions, but it's not terrible sounding, more like a normal sounding ignition. And sense you mention it Tom, the old owners complained of a "fog horn" noise coming from the boiler, but I haven't heard it yet.

Is there something "DIY" that I can do to get closer to the diagnosing the issue?

Tom_133

Pull off that plastic tube where you smell the propane coming from and look inside the piece it's connected to. Do this of course with unit off! You should see whats in this pic.

Should be smooth and solid not cracked or fatigued. Also it shouldn't have a bunch of black soot.

kcopp

Is it possible get a picture of the termination outside?

smithfan

Tom said:

Pull off that plastic tube where you smell the propane coming from and look inside the piece it's connected to. Do this of course with unit off! You should see whats in this pic.

Should be smooth and solid not cracked or fatigued. Also it shouldn't have a bunch of black soot.

Does the plastic part come off pretty easy?

smithfan

Here's the venting..

kcopp

I find it odd they put a Tee Wye there instead of a regular 90 on the intake.
The white pipe should just pop off. Its just on there by friction.

smithfan

Not sure either, but the venting supplement manual does show the Tee Wye as an option.

SWEI

The Vent Supplement copy I have here shows a couple of options for tees on vent terminations, but the only tee they show for a combustion air inlet is at the end of a vertical run.

Please understand: I'm not suggesting that this is the cause of your problem, or even that it's an unsafe condition. It's just not shown in the book.

Tom_133

As kcopp said, the white pipe internally in the boiler just pops off its held by friction. Did you get a chance to look at it?

smithfan

Tom said:

As kcopp said, the white pipe internally in the boiler just pops off its held by friction. Did you get a chance to look at it?

Not yet, I'll check today!! Thanks Tom

smithfan

Tom said:

As kcopp said, the white pipe internally in the boiler just pops off its held by friction. Did you get a chance to look at it?

Sorry, took so long to check..Had some medical issues end of last year so got distracted. But it looks okay to me. What do you think?

kcopp

Its been a while since I looked inside a TT prestige.... that being said. I think something is missing. The intake pipe should be run into that hole.

smithfan

kcopp said:

Its been a while since I looked inside a TT prestige.... that being said. I think something is missing. The intake pipe should be run into that hole.

It does, i took it off to show that o-ring. You'd have to read the entire thread to see why I did so. Trying to identify the cause of a propane smell that happens once or twice a year. I was told to check for cracks on that ring.

Zman

Nothing unusual in the picture.
Have you checked the unions on the gas line. I have seen those leak on several occasions. Usually just takes a little tightening.

smithfan

Zman said:

Nothing unusual in the picture.
Have you checked the unions on the gas line. I have seen those leak on several occasions. Usually just takes a little tightening.

Yes, they are just fine.. Only happens once or twice a winter, usually when it's very cold. I identified where the smell is coming from, and it's the pvc terminal inside the unit.

Steamhead

Have the combustion tested again. If combustion is poor, you can get a smell like unburned gas. This comes from aldehydes, and if you have aldehydes you also have high levels of Carbon Monoxide.

smithfan

Steamhead said:

Have the combustion tested again. If combustion is poor, you can get a smell like unburned gas. This comes from aldehydes, and if you have aldehydes you also have high levels of Carbon Monoxide.

Thanks for the tip. I had it re-piped a year ago, and they spent almost a half hour getting the gas/air mix exactly to manufacturer specs. The smell only happens 2 or 3 times a season. Very unpredictable.