The pressure relief valve on the hydronic system boiler is releasing a little water every time the boiler cycle is almost done and I looked at the gage and its rising to about 30 psi, But I can't figure why the temp is always rising. I already changed the expension tank and TPR so whats now?
Do you have an automatic fill valve? Is there a manual valve in line with it? Try closing the manual valve if there is one. If that solves your problem, adjust and/or replace the automatic fill valve.
If you have a (domestic/potable) hot water coil, that could be leaking into the boiler, too. Shut off the domestic hot water supply on the cold side of the boiler to diagnose that possibility.
I just changed the pressure regulator to a new one (15 psi) and the problem persists Jun 6, 2016 at 14:44
Have you tried shutting OFF the supply to the system (which I suggested doing before you wandered off into replacing parts that might not be broken?) And the supply to a domestic hot water coil, if any (or simply shutoff the main water supply valve for a while which should cover both of those, and then work backwards from what that indicates.)– EcnerwalJun 6, 2016 at 19:37
Yes I did shut off the water and the pressure did not rise and no dripping. Jun 6, 2016 at 20:50
No hot water coil Jun 6, 2016 at 20:51