hot water heating system pressure question

[Rsrtgsprngs]

Need help with a pressure problem. Two floor house with four heating loops. My hot water heating system is 4 yrs. old and has been fine until a few weeks ago. I checked the pressure gage and it read about 50 psi. Turned off the boiler and jiggles the high pressure valve and wosh it dumped water on the floor. Must have been stuck since it is supposed to go off at 30 psi.. Since then service people put in a new fill regulator valve and closed the fill line valve but pressure is still eratic. I drained out several pails of water just to try to maintain about 10 psi when operating. Then a new vent valve was put in. But the pressure still keeps climbing when the boiler gets hot and i'm still draining about 1/2 pail every day. Repair guys don't seem to know what to do. I'd appreciate any guidance. [e-mail]

[Speedy Jim]

Good chance the expansion tank has failed (or needs air charge). On a 4 yr old system, this has to be a bladder-type tank. Did they check that?

Jim

[Dean]

Pressure should be 12 PSI cold and increase to about 18-20 PSI when water is heated up. Do you have an expansion tank with a drain ? If so you might try draining it. From what you say it sounds like you are trying to maintain 10 PSI when cold and hot both which you can not do. If you let out pressure when the water is hot, the automatic feed will just put it back in when the water cools down. Even though you indicated that the make up valve has been closed, I suspect it is either not closed or is closed but defective and still allowing water through.

Rsrtgsprngs wrote:

[Rsrtgsprngs]

Thanks for your reply.

He tapped on it and it did not sound full of water and the bottom was not warm. He did not check the pressure. Can I just put a tire air gage on it to see it if has the 12 lbs. the label says it should be charged with?

So gfar the weather has been mild so I haven't raised the water temp above about 130 degrees. But for winter it's usually 180. That will expand the water more giving higher pressure. Am I right?

Could there be too much water in the system? And if so how do I know not too drain too much?

I love hot water heat but grew up with steam heated radiators and at least the water glass on the boiler let you know if there was too much or too little water in the system.

[Speedy Jim]

Yes, the tire gauge is adequate.

Yes, you'll have even more trouble.

You need the max amount of water in the system; the only air should be in the tank. You determine how much water to add by monitoring the pressure ( as you've been doing).

Yep, completely different. Stop by the library and see if they have a home guide on heating systems. Jim

[Brian V]

big thing here...yes, you can use a tire gauge, but the 12#'s is with an empty system. Theoretically you can take your current system pressure and add 12#'s and that should be fairly close to what your bladder pressure should be.

Yes, 180deg will be a higher pressure, that's what the expension tank is for...to accomadate that pressure.

[m Ransley]

Be sure your auto feed valve and feed are off, set to correct pressure

10-12 cold, drain expansion tank and see if it climbs again. Does the expansion tank have an autrol valve, it could be bad. Ck the lb rating on the relief valve, it should be 35lb. Dont let it go to 50lb. Post at " The Wall" for alot of boiler people and good advise. Alt hvac is a joke.