Hi, I’m have a problem with my hydronic heating system.  We noticed a few weeks ago that water was dripping from our pressure relief valve.  Also, the psi on the gauge read zero.  However, this didn’t appear to affect the actual heating of our house, which is a split level with four floors (including the basement, which is where the heater is).  The heat continued to travel to the top floor when called for. 

Nevertheless, the water coming out of the pressure relief value kept getting worse (like 20 gallons per day) so I shut off the system, drained it and replaced the relief value with a new one thinking that was the issue.  Unfortunately, after refilling the heater it kept leaking water.  On top of that, the psi, which never rose above zero suddenly increased to about 25 despite the system being completely off.  Also, when I did fire the system back on, the psi kept rising and wouldn’t stop.  I finally had to shut off the system when it reached 60 psi. 

After some more research, I suspected a bad expansion tank and sure enough, ours was filled with water and also bad.  So, I replaced that as well and waited until the psi fell down to about 15 before turning the system back on.  Once I did, the psi again started rising and got to 60 before I had shut off the system again.  What’s weird is the fact that the pressure relief valve, which stopped leaking once I installed the new expansion tank, didn’t release any water even at 60 psi. 

For now, I’ve turned our system off again.  The psi is slowly going down.  And I mean slowly.  It took an hour to go from 60 psi to where it is in the photo (around 45). 

The only other thing I can think of is that the pressure reducing valve is also bad and needs to be replaced.  Does this sound right?  Is there anything else it could be or anything else I need to troubleshoot?  Any help would be very much appreciated.  Thanks in advance. 

 

Issue with our house hydronic heating system with psi spiking