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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8688
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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2003 burnham boiler; this winter the relief valve is lifting

Customer Question

2003 burnham boiler; this winter the relief valve is lifting on a regular basis. Extrol tank sounds hollow and is set at 12 bls. Boiler does have heating element for domestic water. I am not sure if aquastat is malfunctioning.
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: T-Stat has not been changed. What filters?
JA: Do you plan on doing the work yourself?
Customer: Yes, I own a machine shop so I have some mechanical and electrical apptitude.
JA: Anything else we should know to help you best?
Customer: There's been no work done to this boiler other than replacing one nozzle. Great product these burnham boilers.
Submitted: 4 months ago.
Category: HVAC
Expert:  Phil replied 4 months ago.

Hello,I am a retired mechanical engineer with 56 years in this business. I will go in depth with you, and up to a 6 hour time limit.

All I ask is please select the ***RATING LINK*** at the top of your page before leaving, that is the only way I am credited through the site.

Rating does not affect your charges nor ability to refund if not satisfied. If you can agree to that, lets continue by all means.

try 20 lbs pressure on the extrol tank, let me know how it goes

Expert:  Phil replied 4 months ago.

25 lbs is standard for most systems

Expert:  Phil replied 4 months ago.

If that seems to help for a while, but later the relief valve starts blowing again, it is likely that make up water feed regulator valve is leaking.

Tell me if you are running the boiler as a sealed system with the make up water valve closed, or if you are running with the make up water valve open

Customer: replied 4 months ago.
I am running with an open valve.
Expert:  Phil replied 4 months ago.

Thanks, ***** ***** case your pressure regulator valve seat is most likely leaking slightly, so that the system will not hold steady pressure at say 25 psig for instance... but city water pressure is getting to the system via the leaking valve seat on the pressure regulator valve.

click here for some pictures

When you have what you need, just rate my work to close the question, I will appreciate it.

Customer: replied 4 months ago.
That certainly sounds possible since City water is higher pressure. At this point I'll have to wait until summer to sweat a new one into the system. Given the fact that I installed this boiler in 2003 when it was brand new, I've never placed a heating element nor a circulating pump. I probably ought to check those as well, nothing lasts forever. He make is a Burnham V8H model.
Customer: replied 4 months ago.
The make
Expert:  Phil replied 4 months ago.

A leaking pressure regulator valve seat in the make up water line is about all that would cause this problem, assuming that the expansion tank is working properly, (does not have a broken diaphragm) and has 25 psig of air pressure in it.

You can test the expansion tank by depressing the schraeder valve core stem on top, if water comes out, the diaphragm is broken. Replace the tank in that case.

Its time to locate the 'rate your expert..' link at the top of your page and rate my work, without a rating I loose my shirt on the question, rating does not affect your charges but is how I earn a living, in exchange I will lock the question so that it stays open and you can get back to me this summer if needed.