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soaddrummer 01-17-2011 05:33 PM

Oil Boiler Pressure Problem
 
I have a OIL fired Boiler system. Its 145,000 BTU Clack HMT-14. My problem is when I have the boiler cold and at 15 psi with the expansion tank at 12psi, while the burner is on warming up the boiler, the pressure seems to shoot up to almost 30psi where I either have to manually shut off the boiler or the PRV shoots on. I have tried to run the system while shutting off the manual supply line and still the same problem. I release the pressure with the manual shut off valve off and start it up again and still the same problem. Any ideas as to why the pressure is building up so much? Could the aquastat and temp gauge on the boiler be wrong/faulty? Maybe the a-stat is telling the boiler to run pass the HI ? Temp gauge on the boiler reads only 85F when the psi is at 26.

Marty S. 01-17-2011 06:05 PM

Beenthere is the boiler guy on here. Sounds to me like you have a expansion tank that's full of water .

Bondo 01-17-2011 06:07 PM

Ayuh,... My guess is, the expansion tank is waterlogged...

soaddrummer 01-17-2011 06:14 PM

I have just checked the expansion tank and it has 12 psi in it and the boiler is at 12 psi as well...when i fired it up the first time this way, the psi went up to 26 and tempt was only at 85F. Should I try it again?

Marty S. 01-17-2011 06:28 PM

Is your expansion tank water heater sized or one of the small bladder types? If it's one of the big ones they shouldn't be more then half full of water.

soaddrummer 01-17-2011 06:56 PM

Quote:

Originally Posted by Marty S. (Post 572494)
Is your expansion tank water heater sized or one of the small bladder types? If it's one of the big ones they shouldn't be more then half full of water.

It is the smaller one with a bladder inside. While the boiler was running there was still air in the xtank.


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