got around to installing my Rinnai 556 FA III-N gas heater last week-placed it for supplementary heat in the living room.Bought this and a couple other Rinnai heaters in used/as is condition-banged up a little and with very little use,the one installed made in 2006.started it up,seemed to be working well but found it stopped and flashing error the next morning-about 4 items came up when diagnostics enabled-changed room temp thermistor location and fixed loose ground to PCB-again found stopped and flashing next morning,flame rod fault given and loose connection at flame rod corrected.next run lasted 1 1/2 days before stoppage for flame fail and gas solenoid valve fault-burner would ignite then blow out when draft blower ramped up.Poking around ,found plug for high fire valve was not making good contact because someone had stuffed meter probes in some of the plugs and bent the contacts-corrected that and so far working good....So far looks like all the problems were caused by a service toad mucking around in it :)
got a heat exchanger overtemp after running ~1 1/2 hrs on high fire,so turned down high fire pressure 1/2"WC to get pressure back in spec and that seems to have it fixed now-running 2 days without a problem :)
Comes to the Rescue!
