hot water boiler problem?? help !!

Matt_29

I have a residential gas hot water boiler, 4 section 85,000btu unit..all brand new 1" copper piping to the three (3) radiators, continuous loop system, bladder style expansion tank, air purger and vent..problem is the boiler feed valve allows fresh water in at 12psi..thats fine, however when the system heats to 180 degrees the water pressure rises to approx. 19-22 psi, thats ok too, but when the systems returns to room temperature, the water pressure does not return to 12 psi on the boiler gauge, it remains high at 19-22psi, even after I deliberately shut down the system for a period of time to check the water pressure accuracy, any ideas ??? the water pressure is slowly continuing to rise and I fear that it will pop off the relief valve as it approaches 30 psi.. thanks for any help!!

Robert O'Connor_7

Matt..

Try and turn off the feed valve to it and see if the pressure stays constant...Robert O'Connor/NJ

Dale

feed valves

They don't work all that well which is why the instructions say to leave them valved off except for purging/filling. Shut it off and drain off to 12# and see what happens. A low water cut off is good insurance too.

Steve_35

Where are

the system circulator, expansion tank and fill valve located in the piping?

Matt_29

yes, the circulator, expansion tank, fill valve are all located in the piping!!

Steve_35

Are you funning me?

Where in the system piping are these devices located relative to the boiler?

Matt_29

yes I was funning you! the air purger with vent and the expansion tank are located in the same location just after the boiler in the supply line and the circulator is located in the return line just before the boiler!

Steve_35

And the fill valve

is located where in the system? Not on the suction side of the circ by any chance?

Matt_29

the Taco fill valve is located after the ball-valve shut-off and just before a 1/2" threaded tee between the air purger and the expansion tank

Steve_35

Other than circ location which shouldn't cause the problem you're seeing all sounds okay. I'd try as someone else suggested.

Close the fill. Drain the pressure down to 12psi cold. See what happens then. You may have a bad fill valve.

Is there a domestic coil or an indirect water heater connected to the system?

Matt_29

There is no other additional system connected. my feeling is, it's the boiler feed valve also, I will watch the pressure readings as I have great heat now and since it is very cold outside, I will wait before I drain and repair/ replace parts!! thanks for the tips!!

Rudy

boiler pressure

check fill valve-pressure in expansion tank.(12psi with 0 system pressure).also check size of tank. extrol 30??

Weezbo

what size and type of by pass do you have?

maybe you are having some severe pressure temp things going on un related to the expansion tank...

Matt L.

There is no bypass, it is a simple closed loop system with only (3) radiators, the gauge on the boiler is a two part gauge, one reading is for water temperature which appears to be exact for the setting of 180 degrees, and the other is water pressure, which seems to get too high at normal boiler temp operation, almost 30 psi at 180 degrees, just seems too high to me...everything is brand new, everything!!