Im no pro but what are you set at. You set the high temp between 170 -
200 . 200 if you need more heat at -20f. If you set it to low your
recirculator pump will run continuosly when it is cold. Pressure is
relative to hight of bldg and your gauge is labeled so as altitude or in
feet. Your boiler has a pressure saftey blow off on it to limit pressure
I set a 3 story at 15 psi cold.

But if you have to ask, you should get a pro to clean and check your
boiler and educate you on your set up . Now is the time, not when it
breaks.