Leaky furnace valve - DIY Chatroom

billinak · 05-16-2006, 02:06 PM

I'll try this without pictures, since they all seem to be too big to post.

I have this leaky valve on my furnace, It's brass, cylindrical, about the size of a pill bottle, and has a knurled cap on the top that you can loosen and tighten. The valve is not in-line with any piping, but sticks out to one side near the pump. The valve leaks, it seems like this or another similar valve has leaked in the past, not too bad, a few drips every few minutes, but enough to be a bother. Is this something I can adjust, or does it need to be replaced?

redline · 05-17-2006, 09:40 AM

Quote:

Originally Posted by billinak

I'll try this without pictures, since they all seem to be too big to post.

I have this leaky valve on my furnace, It's brass, cylindrical, about the size of a pill bottle, and has a knurled cap on the top that you can loosen and tighten. The valve is not in-line with any piping, but sticks out to one side near the pump. The valve leaks, it seems like this or another similar valve has leaked in the past, not too bad, a few drips every few minutes, but enough to be a bother. Is this something I can adjust, or does it need to be replaced?

Is this a hot water system?

Sounds like it is the air vent. Is it leaking at the top or the bottom?
These are inexpensive and you may find it easier to just replace it if the system is older. I would wait until the furnace is not in need of use, like during the summer to change the vent. If the smaller threaded stem breaks off at the bottom them it will take some more work to get the threads out.

With this leaking, making sure that you have make-up (feed valve) water coming into the system.

billinak · 05-17-2006, 01:32 PM

The system was new in 2000, but was installed before we moved in. My understanding is that the boiler provides hot water for the Boilermate hot water tank, as well as the hot water baseboard heaters. I don't think supply should be a problem. The leaks are coming from around the cap on the air vent, does that mean the seal is bad, or is there some kind on pressure irregularity that is forcing the system to vent water?

redline · 05-17-2006, 07:06 PM

Quote:

Originally Posted by billinak

My understanding is that the boiler provides hot water for the Boilermate hot water tank, as well as the hot water baseboard heaters. I don't think supply should be a problem. The leaks are coming from around the cap on the air vent, does that mean the seal is bad, or is there some kind on pressure irregularity that is forcing the system to vent water?

The air vent removes air from the boiler. If air gets in the boiler system then it will makes noises as the water is pumped.

Over time the seal on these air vents fails and it is easier to replace the air vent. They usually sell for under $20.

Look at the web page below and see if your air vent looks like any of these.

http://www.plumbingworld.com/airelim...romsparco.html

billinak · 05-18-2006, 01:24 PM

That's the exact one, the Gold Top Air Vent. I guess I'll change it out this weekend. It doesn't make a lot of noise (yet), but it's still leaking. Thanks for the info!

redline · 05-18-2006, 02:55 PM

Be careful not to break off the threaded lower stem when you remove the old vent.
You may want to turn off the furnace so that the pump is not running.
When you do remove the vent, there will still be water pressure from the small pipe that you unthreaded it from (about 15 psi). Have the new one ready to thread back into the small pipe once you remove the old or water will drain out of the system.

billinak · 05-18-2006, 03:03 PM

Thanks for the tips!

redline · 05-18-2006, 03:06 PM

Hope it all works out for you.

dcam · 11-01-2009, 08:33 PM

did you run into any problems changing the air valve?

did you drain out the furnace as well as shutting it off.

**Scuba_Dave** · 11-01-2009, 09:11 PM

This thread is almost 3.5 years old
Original poster has not been back to this site in almost a year