Pressure relief valve keeps blowing off

Moreken

Good Morning All,

I have a Buderus GA124 Boiler and a LT 200/2 water tank, servicing my wirsbo radiant floor heating and domestic water.
Here is the problem:

The temp/pressure gauge, from the boiler, climbed past 30psi and blew the relief valve. (which is okay, it's suppose to). But now the pressure won't stop building and blowing the relief valve. I have replaced the relief valve and kept the system off until I can figure out the cause of this pressure build.

EBEBRATT-Ed

Could be 1 of 3 problems or a combination.

1. Make up water feeder leaking by is one possibility.
Get the water pressure in the system to 15 psi. Shut the make up water off and keep your eye on things. When the boiler heats up the pressure may rise to the low 20s. It shouldn't go over 25 psi.

2. Expansion tank could be defective. The air pressure in the expansion tank should be 12-15psi. However to chck the air pressure the tank needs to be isolated from or removed from the boiler to check the air pressure.
3. Domestic water coil could be defective leaking water into the boiler water side of the system.


It's difficult to help you troubleshoot. If you can post some good pictures of the boiler and piping we can help

Moreken

Okay once I get home from work I will take some pictures. Currently, I turned off the domestic water to the tank and the pressure stabilized. The radiant floor heating is still running (Girlfriend needs heat), but no domestic hot water.

JUGHNE

Is the feed water to the boiler still on and the pressure normal?

When you get home and turn the domestic water on to the tank and watch the pressure gauge you probably have the answer.

Moreken

Yes the pressure has normalized at 20-25psi, Does this mean that my Heater coil is defective?

JUGHNE

If the water feeder is still on and you turn the domestic water to the tank on and pressure rises it would be most likely the coil.

If you post the pictures more opinions will show up.
There could be some quirk of piping doing something else.

Big Ed_4

If the pressure builds on temperature rise ... There is not enough expansion ... Bladder lost it's charge or tank is defective ....Change the tank ..... Constant high pressure and relief is leaking ... Constant feeding ..