Spill switch tripping, water dripping at vent pipe seam, steam, humid

JohnRL

I have a Weil Mclain gas boiler, a little over 18 years old.

The spill switch trips 15 minutes to a half hour after starts up. There's water dripping at one of the seams in the vent pipe that goes from the draft hood to the chimney. Last night, after it had been running for awhile, I notice steam coming out of the vent hood of the water heater. The basement has been feeling warmer and humid lately too.

I attached a picture so you can see the configuration. I put a piece of foil over the damper motor because the water was dripping on it.

What might the problem be?

Thanks

Jamie Hall

Check that chimney, sooner rather than later. Something may be blocking, or partially blocking the draught. It may be as simple as ice having formed in the chimney (yeah, it can happen) or something more drastic.

Have there been any changes in the operating temperatures of the boiler?

JohnRL

No changes in the temperature as far as I know.

I had a feeling it might be a chimney blockage. I was hoping I was wrong.

Mark Eatherton

I do hope you have carbon monoxide detector alarms throughout your home. This is SERIOUS, and as noted, needs IMMEDIATE attention, if not sooner...

ME

JohnRL

I'm trying to get someone here now

unclejohn

Does it trip when the burner is running or after shuts down. in the picture the damper is shut.

JohnRL

It trips while it's running. It was off in the picture

ChrisJ

Please let us know what they find.

There's of course the opposite possibly, that the boiler and drafthood can't get enough makeup air from the outside. Same result, different cause.

Gordy

Just so you understand the higher level of heat, and humidity is the flue gases dumping into your basement. You need to shut the boiler down until this is resolved!

JohnRL

Yeah, I figured that about the heat and humidity. I have a chimney guy coming at 8:00 tomorrow morning. Tonight we're making do with a couple of space heaters

JUGHNE

Remember that the water heater is just as much of a CO threat as the boiler!!.......you obviously have a partially plugged chimney which it shares.

Jason_13

Could be a cold chimney. Saw a case like this that the chimney came through roof down by the spouting. When hot really cold could not draft properly.
I also agree with the. Combustion air problem. Can you open a basement window and see if problem goes away. One cycle should determine this.

Gordy

If it worked before, and does not now there is issues. Most likely in the flue.

JohnRL

It's cleared. There was a frozen nest of some kind in the flue.

Thanks for the help everyone.

Gordy

Get a chimney cap installed.