I have a question about how to pressurize system when replacing expansion tank. I have successfully taken the old tank off, and am about to go buy a new expansion tank(hopefully already pressurized to 12psi). The boiler is currently at 0 psi, but I'm sure theres still water in there as the old tank was full of water.
I'm not sure what order to install the new tank, do I install it, open the shut off to expansion tank, fill with water, bleed from the baseboards? I also read somewhere I should increase the 12psi to 15 before installing it.. I'm not sure what exactly the psi is for the boiler, the regulator says 12-15psi.
I'm also not sure if the regulator is working properly. I had a plumber come take a look and he said it "might" not be working as well as the expansion tank.. and wanted $700 to replace both.. but I'm not sure how to test it without the expansion tank on. Can I simply turn the water in-let valve and see if it goes above 12 psi? Even without the expansion tank? If anyone knows anything about that, help is greatly appreciated!
Thanks a lot!