I'm in a rental unit, it has 2 GPR 60 units, the one for our side started making loud rattle banging noises all of a sudden for a few minutes than squit, only to do so again about 15or 20 minutes later. The second time was not as crazy, but has me concerned. Landlord claims to have had it inspected. I was a boiler Technition in the Navy, 1200lb D-type, so my landlady thinks I should look at it. Not my responsibility, they don't want to pay anyone to service them I guess, she's a slumlord.