I have an old Kerr wood boiler and we seem to have gotten everything to work but the prv drips when I load it for over night. It seems once the dump zone pipess are hot and the other zones are notcalling for heat the prv startsa to leak. I've looked around and can't find any model or other info on the boiler there is a ul code for maine on it and a kerr plack. There wasa a 40 psi prv on it but our plumber changed it to a 30 and now were getting the drip. I'm nervouse about running when icant watch it the 40 psi blew off when we first bought the house. My fualt had furnace off. And Started the boil not knowing that I shut off the circulators as well. I'm new to this