Steam Heat – How much pressure?
Hi everyone,
Quick question – what’s the normal pressure expected in a steam boiler?
I wrote earlier about my one-pipe steam boiler (oil to gas conversion) with an additional hot water loop on it to the kitchen where the pressure valve was popping off when the system got warmed up. I’m having trouble getting a plumber who knows anything about steam heat, this being the plumbing/heating busy season and all… Plus I’m worried that the next guy is going to tell me that it’s new boiler time. It’s like not wanting to go to the doctor because you think you have cancer…
The pressure in the system builds up to 13 or 14 on the gauge (PSI, I’m assuming) before the pressure relief valve blows off. What’s normal for this type of system? Is the valve defective, or is the pressure getting too high? I’m trying opening all my radiators full bore to see if that helps.
Any suggestions greatly appreciated,
Ben
Replies
My understanding is that 13-14 is typical, but that systems vary.
Are the valves on the radiators working right? They are suppopsed to be open to allow the setam to rise into the radiators, then close as the radiators warm to keep the steam in.
There is a website devoted to steam and hot water heat, I don't have the url handy but try a google search.
the website you are looking for is:
heatinghelp.com
steam specialists.
the pressure you state sounds WAY too high.
Residential systems usually operate at 2psi or less.
Too much pressure causes unintended consequences and wasted heating money (high pressure = high friction losses).
The lowest pressure possible is your goal.
My two pipe system, after following advice from the experts (buy a few of the books on that web site to learn all about how your system is supposed to work and to find the ways to correct what may have settled over the years, or might have been botched up by others over the years) my system runs at almost zero psi. I bought a fancy gauge to measure ounces / square inch and the needle still hardly comes off its stop during the coldest days of the year. Very, very efficient.
Norm, thanks, I quess I was thinking of hot water heat.
Ben,
"- what's the normal pressure expected in a steam boiler?"
What's the normal milage expected for an automoblie? The answer is, it depends on the automobile.
No one can tell you that without more information on the boiiler. Anything else is a guess, and although some very good ones have been made, they are only guesses.
" I'm having trouble getting a plumber who knows anything about
steam heat, this being the plumbing/heating busy season and all..." I wouldn't look for a plumber, I would look for a good heating contractor. They are out there. BTW, did you ever get a new relief valve?
Tim
Well, thinking through the system when I was at work and reading through heatinghelp.com, I went back home and checked the radiators. My three biggest radiators were turned off, and a couple upstairs were turned down as well (after reading heatinghelp, it turns out that steam one pipes should be treated as binary - on or off, nothing in between). After opening all the valves full bore, the pressure is only 2-3 PSI
Now, my glass water level indicator was hissing steam when the pressure was high. In trying to fix the seal, I busted it. I got the wrong size glass yesterday - my wife got it cut down today while I'm here at work. So the lower pressure COULD be due to a low water level, but I don't think so. I'll let you know when I get the glass fixed tonight.
I decided against wrenching off the pressure valve myself and replacing it with a new one. My reading (just as Norm said (Could he be the real Norm?)) says that lower pressure is much more typical. If something is pushing the system up that high, then I need someone smarter than me to look at it.
Thanks for all the advice,
Ben