What is a safe PSI for a residential cast Irom Boiler?
12-15 PSI when cold on a hydronic boiler.It shouldn't go over 25 PSI. when heated,relief valve opens at 30PSI.---3-5 PSI. on steam boiler,relief valve opens at 15PSI.
Your PSI is low ! Average is from 12 to18 Lbs. If cold and at 25 or higher, when it heat up it may get past 30lbs and blow the safety relief valve.
