Posted by cory n on May 11, 2001 at 17:59:04:
In Reply to: Re: pressure build up posted by TB on May 10, 2001 at 22:48:32:
: If you don't need the heat, shut off the boiler so it won't fire, and drain the boiler to about 10 pounds of pressure, and let it set for a hour or so without it fireing. If the psi climes to 30#+ most likely its the psi reducing fill valve. If the psi stayes the same, find the expansion tank, isolate it from the system, there should be a valve to shut off, on the line to the exp. tank. If it was off, it shouldnt be, and may be your problem, MAKE SURE THIS VALVE IS OPEN WHEN YOU FIRE UP THE BOILER . Drain the exp tank of water through a valve on the tank , remember, if no air gets in to the tank to replace the water draining out it may stop draining but that does not mean the tank is empty. If the tank looks like a propane cylinder kind of, and has a schrader valve (like on a bycicle tire to fill it up w/air) depress the valve stem quickly, if air comes out its probly ok, check the psi. If water comes out,replace the tank. If its the original tank you probly don't have a bladder tank, so just drain it. Once its drained, and the isolation valve is open, (some water will rush back into the tank, fire off the boiler, and watch it. If the psi climbes more than a few degrees shut it down, and call a heating tech in. These are the simplest fixes, if they don't work, call a tech. If you get the bright idea to plug the leaking relief valve, you've just created a bomb, capable of leveling your house.
Maybe it will help if i give a slight overview of my system.
it has a steel tank about 5-10 gallon i think it is fastned to the ceiling about 4 feet over the top of the boiler it has a drain plug in the bottom and a pipe going out the back the pipe runs down into the back of the boiler about four inches about the top of the boiler is a tee with the 30 psi blow off vavle and a pipe leading to the drain. the front of the boiler has a large square pressure gauge. the only other vavle is on the bottom of the boiler i use to drain it. it is just a regular water valve. the boiler has been off for about 3 days and it still builds up pressure after i drain it. it only has the pilot light going. one more thing should it be drained for the summer or can i leave the water in it. I have been draining it.
by the way i worked on piping systems in the navy (just not boilers) so i do know enuff not to plug a blow off valve lol thanks for the tip though.
p.s. where would the psi reducing valve be? it is a natural gas system by the way.
Post a Followup