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If the pressure rises as the temp rises to the point where the relief valve leaks then you have an expansion problem. The tank could be too small or may have failed
If you have an old style expansion tank (usually between the floor joists ) then you could try draining the tank or installing a new diaphragm type
yeah a problem with the tank was my guess too. Is there anyway to test it?
Which type do you have
old style or diaphragm
its is an old looking vertical cylinder about 10" wide and 18" high
old style I'm sure
If it doesn't have a fitting to let air into the tank then you won't get water out of it with a hose attached. The only way to drain it is into a bucket.
It will take quite a while as air gets sucked into the tank as it's draining
So you either drain all the water out of the old tank then re-open the valve to the system SLOWLY. or you replce the tank with a modern one
sounds like I'd be better off with a modern one
any suggestions on size of tank needed for a 93000 btu/hr output furnace?
If you have copper baseboard or convectors you would use a #30. If you have cast iron baseboard or radiators then you need a #60Indeed. You can tie it into the same line as the old tank unless you have an air scoop on the heating main with a 1/2" female tapping in the bottom. If so then you could just screw it into this tapping.
okay, I'll go ahead and get one tomorrow. Thanks for the help.
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