About 8 months ago, the Extol diaphragm style expansion tank on my boiler failed (diaphragm failure) and needed to be replaced. Now, I think I might be having the start of the same problem again. Symptoms include:
1. Pipes leading to hydro-air handlers sometimes make a gurgling noise, leading me to believe air got into the closed system
2. Bottom of expansion tank (air side) felt warm (though nowhere near as hot as the top portion).
When I tap the bottom half of the tank, it still makes a hollow tinging sound leading me to believe it's not flooded yet, but the other two symptoms worry me a bit.
I checked the air pressure on the expansion tank and it looks to be between 10 and 12 psi give or take. It's a car tire gauge I'm using, so not sure how accurate it is.
Lastly, The pressure on the boiler seems okay and the temp maxes out at 170.
1. Should I be concerned at this point and call in a pro?
2. If this is a problem again, is it just bad luck or could there be other causes for this repeated failure?
Thanks for any input.