Hey all. I have a home with a 12 y/o boiler and radiator heating, 2 zones. This is my second winter in the house. Last year I had no problem with the pressure. However, this year, my pressure gauge is through the roof. When I run zone 2, the preasure increases into the hundreds, about 120psi at about 180 degrees. I know, I know, I do shut it off right away. Zone 2 runs just fine at 20 psi. It holds steady cold at 12 or so psi. Anyway, I have drained the expansion tank, kind of. It kept draining, and draining, and draining. The water never stopped. Did I miss something? However, when I did do that, fired it back up, it didn't raise the psi too fast, but it did increase to over 100psi. Any ideas? I know nothing about boilers. I have pulled a little diagram that somebody had posted on this site but I'm still stuck. Thanks!

 

Zone 1 works just fine, not zone 2. Also, gauge only goes to 55psi, so it gets up to 50 psi, not
100+ UPDATE AGAIN: Zone 1 doesn't work just fine... guess I need help figuring out which valve to turn on and off. I have about 7 to choose from.

Check out pictures of my boiler at: Login to a private Photobucket.com album

Password is boiler

 

Rick, you are reading the gauge wrong. There is no way you have 120 PSI in your system. It is highly unlikely that your gauge even reads that high! [edit: just read your second post and see that you figured that part out. But even 50 PSI is unlikely... especially if the relief valve is not spewing steam and hot water] Your gauge could well be defective.

Would it be too much to ask for you to rotate all those sideways pics to upright? It's very difficult to keep turning my monitor on it's side.

 

Ok, all the pics are flipped, sorry about that.. Yeah, I don't really trust my releif valve, thats all . I tried draining the expansion tank again. It drained all out until it bubbled and sucked air. Still some water in it. Is it normal that when I turn the valve back on that it is to fill back up with water? Thats what it did, with cold water. I have never had hot water in the expansion tank.....

 

OK, that's better... Yes, the expansion tank will fill with water to about 1/2 to 2/3 full but there will be an air bubble trapped at the top... that's normal.

I would first make sure my pressure gauge was reading correctly, and as a safety measure, would definitely replace the relief valve if there is any doubt about it at all. then work from there...