How to add pressure to boiler system?

WNB

We've got a 2008 Slantfin Sentry hit water boiler, and it works well for the most part, except for a few baseboards that need to be bled every couple months. Eventually this causes the pressure to drop a lot. I forgot to ask my HVAC guy about how to add pressure last time he was here, and I was wondering if someone could point me to the right lever?

Thanks in advance!

https://imgur.com/a/n7KUOey

EBEBRATT-Ed

In your second picture down there is a yellow handle valve to the left and below the expansion tank in the horizontal 1/2" copper pipe. The valve looks like it is closed. Open it until you get 12-15 psi on the boiler gauge then close it.

Not the yellow handle valve to the left in the larger vertical pipe.


You need to find out where the water is going. If you keep losing water and adding new water that is not good for the boiler

WNB

EBEBRATT-Ed said:

In your second picture down there is a yellow handle valve to the left and below the expansion tank in the horizontal 1/2" copper pipe. The valve looks like it is closed. Open it until you get 12-15 psi on the boiler gauge then close it. Not the yellow handle valve to the left in the larger vertical pipe. You need to find out where the water is going. If you keep losing water and adding new water that is not good for the boiler

Thank you! I gave that a try and the pressure doesn't seem to change when I open that valve... Is there anything thing else I might be missing? Otherwise I'll call tomorrow and have the professional take a look at it.

My HVAC guy's theory is that there may be a miniscule leak somewhere that's just evaporating. There's a lot of weird stuff with this house...

yellowdog

looks like you need to open the blue handled valve too.