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f9 flier 04-27-2011 02:57 PM

pressure relief valve leaks
I have a crown boiler that is about 16 years old. Just recently the pressure relief valve started leaking. I replaced bothe the pressure relief valve and the expansion tank and the pressure still bulds up over the 30psi. Any suggestions?

COLDIRON 04-27-2011 04:20 PM

Check the automatic fill valve, it's probably not shutting off the water coming into the boiler.

how 04-27-2011 05:36 PM

Could be a anything that affects temp or pressure.
If the water pressure creeps up to 30+ psi when the boiler is cold, then your water pressure reducing valve may just need to be adjusted but will usually need to be replaced.
If it only gets up there when the boiler is hot then make sure the piping connecting to the exp tank is not plugged. Some poor configurations can allow sediment to collect on that leg.
Poor pump circulation? A gate valve thats partially closed? An air lock in one of the rads?
What is you temp reading at the tridicator?
Submit pictures of your set up if you can't sort it out.

Yesterday I had a boiler doing that because the little electrical switch on a zone valve was stuck "on" allowing the boiler to fire up without a zone valve actually being open.

secutanudu 04-27-2011 06:54 PM

Sounds like a bad autofill valve to me...

plumber666 04-28-2011 07:14 AM

Fill valve.

f9 flier 04-28-2011 08:02 AM

Thanks guys. I appreciate the help.

f9 flier 05-08-2011 11:31 AM

Is the aquastat relay the auto-feed valve?

COLDIRON 05-08-2011 12:37 PM

No the water auto feed valve has no electric to it , it just works off pressure in the system and pressure from the city. It usually looks sort of like a brass bell with a screw on top.

secutanudu 05-08-2011 02:23 PM

biggles 05-08-2011 03:31 PM

red regulater is tagged for 12lbs water feed then the boiler heats the water and the tank takes the expansion but alll that should be under 30psi relief and when the thermostat is satisfied and cucles off the boiler

f9 flier 05-08-2011 03:37 PM

Thanks. I have replaced the pressure regulator, the expansion tank, the circulating pump and the pressure reilief valve. It still builds pressure. Any suggestions?

how 05-08-2011 06:22 PM

unusual residential boiler psi problem
OK...You have done the normal things for pressure control so if the new press reg was installed facing the right way? Then...

Does the boiler always show a high psi or does it fluxuate.
If it is 12- 25 psi and only goes up over 30+psi when it's running then...

Watch your boiler go from cool to hot. Tell us when the boiler pressure starts to climb in psi.
Normally in a common boiler the thermostat calls for heat/ the zone valve will open and trip an electrical connection if you have more than one heating zone/ if you have a damper motor on the vent it will also need to open which will trip another switch/ then the main gas will start firing/ the pump will come on right away or may wait for the aquastat temp controls depending on how it's wired/ hot water will start flowing out of the boiler furthest from the pump while cooler water will be returning to the pump/ you will feel this on the piping. The main gas will continue to fire until
the thermostat shuts it off although your aquastat may turn it on & off during the process to prevent the water from getting too hot. When the thermostat does shut off the main gas, the pump will usually shut down at the same time.

With this all in mind, tell us WHEN in this process does the pressure reading change and to what?

Do you have a slaved system that is also heating your domestic water through your boiler or is your Hot water tank independant.

f9 flier 05-08-2011 07:01 PM

I have an indirect domestic hot water heater. With the outside temp being 80+ lately the only zone that opens is the hot water heater. I can bleed the pressure off (down to about 15psi) and is climbs but very slowly. It does howerver, climb faster if the boiler is running. I have not tried to shut the boiler down to see if it still climbs.

COLDIRON 05-09-2011 05:29 AM

Explain your "Indirect water Heater".

Daniel Holzman 05-09-2011 07:40 AM

I had exactly the same problem, and I also had an indirect hot water heater. My indirect heater consisted of a coil of copper pipe inside the boiler, which circulated hot boiler water through a storage tank, where the domestic water was heated. In my case, there was a small leak in the coil inside the boiler. Since the pressure in the indirect coil is house pressure (50 psi in my case), and is not controlled by the boiler makeup water pressure regulator, the effect of a leak in the coil is to pressurize the water in the boiler to house pressure.

I could have replaced the coil, which would have cost about $700, and came with no guarantees, because my boiler is old (1959), and the bolts holding the coils to the boiler are rusty and suspect. I chose to purchase an electric hot water heater and dismantle the indirect system. I capped off the coil lines where they enter the boiler. Problem solved.

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