Pressure lost on closed system - LEAK?

Mark_25

My new system was running fine over the winter, and now that it's been shut off for the summer, I noticed that the pressure gage on the boiler is reading zero. I know that there's supposed to be some expansion when the system is hot, but when it's cold, does the water/glycol mix contract enough to remove all pressure from the system? It ran fine with no leaks and there aren't any obvious leaks now either. When I crack a valve, I get fluid spraying out, so it's not dry by any means. What pressure should a system read during cold shutdown?

Thanks.

JB_2

pressure

mark - do you have access to another gauge, one with a hose connection that you can put on the boiler drain?. maybe a gauge that reads 0-30 psi?. sometimes the boiler tridacater is not the most accurate. could be off.also if this is a heating boiler only you might consider installing an opperating control for summer. rather than shutting off the system, maintain a low temp. 100-110 deg. .condensation and fuel by-products do not mix well. jb. p.s. this is just a step in finding what is wrong,jb.

Mark_25

I could put a gage on it pretty easy. It's got a Honeywell outdoor reset on it now. I don't really think I want to run it through the summer. too damn hot in there already. (It's a floor heated shop)
I think I'm going to put some more water in the system, and see if the pressure goes down again. If it does, I'll know I've got a leaker.

Mike T., Swampeast MO

Your compression tank could be a problem. If the air charge was low through the heating season because of a diaphragm leak, you'd get a hefty pressure drop when the system was shut down.

If the air fill valve started leaking, pressure would drop as well.

Hopefully you have a valve in the line to the tank because you have to remove all pressure from the water side of the tank to set/check the air charge on the other side of the diaphragm. 12 psi is "normal" so remove water pressure by draining some/all water, set air side to 12 pounds or so and wait a month or two with JUST the air in the tank. If air pressure drops diaphragm or fill valve are bad.