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psi dropped, no signs of water leaking
I can't believe I'm about to be this guy. I swear there are no leaks! Both the wife and I checked for leaks many times - like crazed maniacs, I'll add. All my work is still exposed and there is no sign of water leaking, no rust spots, no damp spots, no pipes under slabs, all exposed, nothing. There is only 1 auto air vent above the expansion tank, and I'm pumping away. All the other air vents are manual.
System psi was at zero when I walked by it today. I barely had to add any water to bring it up to 15psi. The system has been running for like 6+ weeks and at temps as high as 165. Every time I notice the gauge at the expansion tank, it hasn't been below 15psi. Over the last week+ I did notice [heard] some air accumulating in a couple second floor radiators.
This same type of thing happened to me just 2-3 weeks after commissioning the system so I'm hoping someone will tell me that I just did a poor job of removing the air when I commissioned the system, and that after it ran for a while - and at higher temps - air gradually came around, hit a vent, and the pressure drops. I'd like to think that is what I'm seeing here. Is this theory a dream or possibility?
DIY'er ... ripped out a perfectly good forced-air furnace and replaced it with hot water & radiators.