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reblynferg
11-22-04, 06:55 PM
We have an electric hydronic block heating system. It uses basboard radiation. When heating from 62 to 66 degrees, the pressure goes over 30psi and PRV is blowing. We have bled all of the air from the lines. Any suggestions as to what to check? :confused:
arkayassoc
11-22-04, 07:36 PM
We have an electric hydronic block heating system. It uses basboard radiation. When heating from 62 to 66 degrees, the pressure goes over 30psi and PRV is blowing. We have bled all of the air from the lines. Any suggestions as to what to check? :confused:

Sounds like you have too much water in the system. Check the pressure guage on the boiler. It should be in the 15 - 18 psi range. Anything higher indicates too much water.

You will need to drain some water from the boiler. But first, close the shutoff valve that should be upstream from the auto-fill valve. Then drain water from the boiler to get the pressure down. You may need to adjust the auto-fill valve to a lower pressure setting. It is a bell-shaped valve that has a stem or thumbscrew out of the top of it. Loosen the thumbscrew to decrease the pressure of the make-up water.

Are you new to this house or this system? Did you have the problem last winter? If you need more help, post back.
reblynferg
11-23-04, 06:20 AM
We have had this system for three years. The first two, upon winter start-up, pressure problems were releived by purging the air. This year, it is not working. The pressure continues to be high.
arkayassoc
11-23-04, 06:41 AM
Believe you have a problem with the auto-fill valve. Either it is set too high, or it needs replaced. It is easy to check, after you drain some water from the system. Follow instructions from previous post, and let us know what happens.
Ed Imeduc
11-23-04, 10:51 AM
What do you have there for an expansion tank and is it ok. If its a bladder tank do you get any water out of the schrader valve on it ??

ED ;)
reblynferg
11-23-04, 04:51 PM
When the system is off and the water is cool, the pressure reads at 12 psi.
George2002
11-24-04, 04:43 AM
....the pressure reads 12 at the expansion tank or the boiler??
reblynferg
11-24-04, 05:36 AM
12 at the boiler. we don't have a guage at the expansion tank.
arkayassoc
11-24-04, 05:43 AM
12 at the boiler. we don't have a guage at the expansion tank.

Ed asked you "What do you have there for an expansion tank and is it ok. If its a bladder tank do you get any water out of the schrader valve on it ??"

Can you let us know about the expansion tank? If it is not a bladder tank, is it liquid full?
reblynferg
11-26-04, 12:30 PM
We got out the tire guage to read the pressure on the tank. It did not register anything, so we "charged" it to 13 psi. Less than an hour later, it registered 0 again. So we assumed the tank was bad. Any early morning trip to Lowe's ended up with a tank that would be ok, but wasn't exactly right. We stopped at the local plumbing & heating supplier, they had the exact tank for our system. The old tank was full of water when we removed it! That must have been the problem! Thanks for your help!! :)