T&p

rex

alright i installed a 140 btu munchkin boiler with a 80 gallon super store tank in a customers house...this is a open loop system heats 2500 sqf of floor....

my problem is the damn t&p on the storage tank keeps blowing off.....and its not temp related....the whole sub has a high pressure problem..so i installed a whole house pressure reducing valve.... reducing the pressure off the 1" main to 65psi.....t%p held for about a week.HO calls hey its blowing off again....ok im gonna come and install a expansion tank near the storage tank.....so every thing is good for another week calls again....so i replace the t&p thinking wow im a idiot its been the t&p the whole time.nope still blowing off....i guess its not blowing off its more like a little trickle the HO has been awsome about it but for what he paid for the system i need to make this right......

so any suggestions?

KillerToiletSpider

What size expansion tank did you install, and what kind of pump are you using for the boiler?

__________________
A flush is better than a full house.

rex

id have to look on the tank size...but im using a taco 011 on the tank loop and a taco 010 for the boiler loop....and 007's for each manifold.....i should also add that i have 6 of these boliers in houses in this sub and not one problem....

KillerToiletSpider

Have you checked the output temp on the boiler? it may be a bad temp control valve causing the boiler to overheat the water.

__________________
A flush is better than a full house.

Ron The Plumber

Did you charge the tank higher then the reduced pressure?

Grumpyplumber

When you say it's not temp related I assume you checked the temp right out of the Superstor.
I'm wondering if you forgot the check on the DHW loop or it's bad, might be overheating if the heats been kicking on.
Also, the aquastat...but these points are moot if the actual hot water temperature is ok at the time the t&p is weeping.