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.