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Rinnai 75lsi Tankless Water Heater - water flow servo/sensor housing

slewth Member Posts: 1
Greetings... I have a Rinnai 75lsi (propane) tankless water heater that I flush twice a year. I do the descaling flush (normal flow direction) using distilled white vinegar and clean the filter screen/plug. However, is there a way to back wash the system or more importantly clean the water flow servo/sensor housing without removing it from the main unit? I think some debris has gotten past the filter and may be fouling the flow sensor/housing. I'll appreciate your insights. Thanks.


  • Jack
    Jack Member Posts: 1,046
    No! You can remove the filter and, if you can get your head into a position where you can see up into the the turbine. If you able to do this you can remove the snap ring and gingerly remove the turbine body with a set of needle nose pliers. Backflushing drives whatever crap is in the HX back to the turbine guaranteeing more problems. I would suggest when flushing the unit that you put a filter on the vinegar leaving the unit so you catch the crap before pumping it back into the unit.