Wind and gas/combustion smell on triangle tube

wrxz24

Hi all, got a call from my wife about a propane smell in the house. Came home and could smell a little but not the distinct smell of raw propane.

So, went to my boiler triangle tube 110 and inspected it. The boiler fired fine and there were no leaks at gas connections.
However, after the boiler cycled, the wind was blowing real hard and I got a smell coming from the intake pipe.
Is it possible for wind to blow hard enough to enter the exhaust and up through the heat exchanger/ combustion side and out the intake? That is where the smell is coming from. Thanks in advance.

Jamie Hall

Yes, it is possible -- if the boiler isn't vented properly for the house and the situation.

wrxz24

Thanks, the venting is to spec but the wind was ridiculous this afternoon. Not bad now and the smell is gone.

unclejohn

You can check for exhaust gas recirculation by removing the gray intake pipe off the gas valve. There is a black orifice there, if that orifice is worn or pitted you are recirculating ex. gasses into the air in pipe.

wrxz24

Thanks. Will do.

icesailor

Is the intake connected to the outside or is it using the inside for make up air? If so, on high wind days, the draft osculates from positive to negative inside in side a building in high wind conditions.

Look at the water in a toilet bow on a windy day. If the water in the bowl is going up and down in a wind storm. the high gusts are under lower atmospheric pressures while the inside also goes up and down. The pressure between the inside and the outside is trying to equalize through the venting. The plumbing vent and the boiler venting.

Very common in high wind conditions.

wrxz24

The intake is the small section of pipe inside of the cabinet but the air comes from the vent pipe that comes from the top and outside the house. Should the intake pipe and vent to the outside be connected?

SWEI

wrxz24 said:

The intake is the small section of pipe inside of the cabinet but the air comes from the vent pipe that comes from the top and outside the house. Should the intake pipe and vent to the outside be connected?

In a word, NO. This indirect intake design allows leaves and bugs to fall to the bottom of the cabinet rather than being sucked into the gas valve. It also preheats the combustion air somewhat. Connecting them together would also exacerbate the pressure variations caused by wind (you're removing a buffer tank of sorts from the intake line.)

wrxz24

Good to know. Thanks

wrxz24

Hi all, I just had my boiler serviced and the tech noticed the smell and put a device that detects gas up inside the intake and it beeped pretty fast. He believes that the gas valve is bad and needs to be replaced. Are gas valves prone to fail in only 4years of service?

Tim McElwain

Ice good to hear from you where have you been?

kcopp

Tim.
This was an old post from 2014. The OP brought it back up.
Still would be good to hear from Ice again....

delta T

@Tim McElwain I hate to burst your bubble, that post was from 2014. I miss Ice too, wish he would come back, always some good solid insightful, no BS advice. I got fooled at first too and got excited.... but alas, no.

delta T

OP,

There are a few things I would check before spending the $ on a new gas valve. first of all, was this gas check done after the unit had been sitting idle for a half hour or so? Those meters can be pretty touchy and I would not be surprised that after normal operation a small amount of gas could be detectable. I would check for gas only after a significant period of time has passed with the unit completely shut off (with the gas on) to be sure. I have seen a gas valve fail after 4 years, but it is very very rare. are there any other apparent problems?

What is your venting termination like, Concentric? two pipe? vertical? horizontal?

wrxz24

null
Yes, the boiler was on standby and cool and I still was able to smell gas coming from the intake pipe. I took it off and still smelled gas coming from the opening. It kind of feels like warm gas blowing out even though the boiler is cool.
The boiler is running a tad rich and it was having frequent failed ignitions hence the service to begin with. He believes it is a faulty gas valve and to me, maybe the valve doesn't fully close after the boiler cycles?

Leon82

It may be a stretch but some older pipe dopes give off hydrocarbons.

wrxz24

null
It's just in one spot and no pipe dope around that I can see.

Tim McElwain

I do not know what the specs are on European Negative Pressure gas valves but American valves can have an allowable amount of gas leakage usually not detectable by smell unless the gas supplier is over charging the fuel with odorant (ethyl mercaptan). I would have someone with a very good gas detector check to see what percent gas you are getting. With natural gas anything less than 4% is not able to ignite and for LP anything less than 2.1%.

wrxz24

Thanks, I will have that checked out by my new gas supplier.