On Mar 2, 3:04 pm, "Edwin Pawlowski" wrote:
"Andrew" wrote in message

oups.com...

The pressure overflow valve on my furnace is leaking. It's a gas
fired hot water radiator system. I recently replaced the corroded
original, thinking that that was the problem, but it is persisting.
Here are the symptoms: The pressure gauge on the unit shows 30psi
which is the burst point for the pressure valve, hence the leak. If I
trigger the valve and fill up a bucket with water, I can get the
pressure gauge down to around zero, but within an hour it's back up to
30psi. I think the problem may be that the water supply valve to the
furnace has failed, allowing water to get by and raise the pressure.
Does that sound right? It feels like there's water flowing in the
supply line after I trigger the pressure relief valve, but the supply
has a ball valve, and I thought those things never failed...Could
there be some grit or corrosion in it?

I've never seen a furnace with a pressure relief valve. All boilers have
them though. Furnaces heat air, boilers heat water or make steam.

Yes, it sounds like your regulator and fill valve are shot. I know of some
that are 50 years old and still working, but on my boiler, 7 years is a
stretch.

You say the ball vale is in line, but that is probably open for water to
self fill if needed. Temporarily, you may get buy turning it off. Unless,
or course, that is leaking by also. That can happen

Thanks for clearing up the furnace/boiler distinction. The ball valve
is in-line, and it is definitely closed. It always has been except
when I've re-filled the system after draining it. The cold water
from the city comes in through this ball valve to a tee that goes
*down* into the circulator pump and *up* to supply the radiators. Is
this ball valve different from the "regulator" and "fill valve"? Are
those two different things or the same thing? Here's the manual for
my unit. Figure 5 shows the plumbing configuration:

http://www.crownboiler.com/manuals/c...20ABF-EID).pdf

Thanks, Andrew