Winter Wonder Land

I posted this on a heating forum I joined yesterday:


I have hot water heat with a boiler, base board heaters, and a few old radiators. Yesterday, my wife called me and told me there was a bunch of water all over our basement floor and the boiler was banging. I told her to turn off the boiler and I left work. When I got home, I found that the pressure relief valve was dripping, but there was a LOT of water on the floor, more than from just a few drops.

I switched on the boiler and right away the banging started. About three loud knocks, coming directly from the boiler. I checked the pressure guage it was at about 14/lbs. The water temp was cold since the boiler had been off for a few hours. I let the system start to heat up, and as the water temp reached about 190, the relief valve really opened up, and hot steaming water started poring out instead of dripping. All this time the knocking persisted about every 4-5 minutes.

I shut the boiler off and went upstairs and opened each of the radiators and baseboard vents. There was a small amount of air in each one, but nothing major. Went back down and switched the boiler back on and it got up to 190 and started pouring out water again. Keep in mind the pressure had been at 14-15/lbs. steadily.

Next I isolated the expansion tank and drained it completely. It was full at about 30 gallons, with out a lot of pressure. When it was drained I opened the tank up again and the pressure instantly dropped to about 6/lbs. I thought I had solved my problem and that the tank was just water logged. I turned the boiler back on, hoping everything was okay, but I noticed that the relief valve was still dripping despite the drop in pressure and the cold water. The temp and pressure built in the system until it got to 190 degrees and 14-15/lbs again and the steaming water started pouring out again.

Pretty frustrated I shut the system down for the night and sent my wife and kids to sleep at the in=laws (It's about 5 degrees at night here). After work today, I went to Home Depot and the guy there thought the over heating of the system was caused by the excessive pressure and that I needed to get my pressure down to about 10-12/lbs. He gave me a feed pressure regulator, thinking mine was broken. When I got home I went to look for my existing regulator and found that I don't have one. So I brought that back, thinking that if the system didn't need one up till now then that's not what's causing my problem.

The Home Depot guy agreed with that assessment and gave me some other advice. He told me to again drain the expansion tank, after the tank was empty I was to open it up again and wait for the pressure to start rising. When the pressure got to about 9/lbs. he wanted me to shut off the expansion tank and let the system run cold without the tank to see if the pressure stabilizes.

I did all this, and shut off the tank when it got to about 9/lbs, which took about 10 minutes. However, the second I turned off the tank, the pressure started to shoot up very quickly. When it got to about 14/lbs. again I opened the expansion tank back up and the pressure quickly dropped back down to about 9/lbs. I also noticed when the tank was closed I could hear the city water flowing into the system. This gave me the idea to turn off the cold water intake, so I did.

I've been running the system now for about a half an hour with the intake turned off. The water is no longer boiling out the relief valve because the temp has stabilized at about 185. The pressure is stable at about 10/lbs. However, the relief valve is still dripping. It drips slowly while the water is at about 180, and when it gets to about 185 it pours a little quicker until it cools back down a tad.

The pipes are slowly warming up, and I mean SLOWLY.

A couple of questions:

1) How long can my system run without the city water coming in? It's still leaking from the valve, so I've been opening up the city water as I empty out the bucket to replace what I loose. But I'm not going to let it stay open because then the pressure gets back up to 14-15/lbs.

2) Why is my valve still leaking even if the water temp is 60 degrees and the pressure is at 6/lbs? Do I probably need a new valve?

3) Any idea why this may have happened all of a sudden?

4) What's with the banging coming from the boiler?

5) The pipes on the second floor are still ice cold. Is 10/lbs. of pressure enough to get hot water up there?

6) Could this be a problem with the circulation pump? The banging seams to be coming from it's vicinity, but it's hard to tell.

Yeah, I know that's a lot, but it's been a pretty stressful and scary couple of days. We just got this house about a year and a half a go. The boiler worked fine last winter, now this winter (after the warranty ran out) it's killing me. I have no money, so replacing it is a pretty scary thought, considering I've heard they cost like 5 grand to get done. That would take me months to save.

I really know NOTHING about plumbing/heating. Everything I just typed I wouldn't be able to yesterday morning, but I've been reading like crazy on here and similar forums trying to learn. I'm usually a pretty quick study and I'm not afraid to try and fix things I know nothing about.

So... any ideas?

Scott