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Rinnai RUCS65i - have to cycle power to restart

MikeW32MikeW32 Posts: 5Member
edited January 6 in Domestic Hot Water
This is an indoor unit but when the temp gets down to the 30's the unit tends not to start. I can unplug and plug back in and it will start most of the time. It might be a coincidence with the temp. I have performed all the flushing and cleaning of filters. No error codes and nothing at all on the small screen.

I am thinking a bad pc board, freeze sensor. Thoughts?


  • SuperTechSuperTech Posts: 1,164Member
    Does it draw it's combustion air from outside? It may be running too lean with the cold make up air.
  • MikeW32MikeW32 Posts: 5Member
    I am not sure but all the other houses around me have the same heater and installation and do not have this issue.
  • pecmsgpecmsg Posts: 1,135Member
    Record the trouble code before resetting. Inform your service provider of the code when making the appointment.
  • MikeW32MikeW32 Posts: 5Member
    Is there a capacitor in this heater? Once it is running and turns off, it will seem to work fine until it is not used for alot of hours (overnight).
  • MikeW32MikeW32 Posts: 5Member
    no service codes at all. It is like the unit has no power. After unplugging and plug back in 2 dash appear and it works.
  • CharleyCharley Posts: 9Member
    I do not know, but wonder if the gas to the heater is affected by the cold.
  • MikeW32MikeW32 Posts: 5Member
    This has got to be electrical related. Either the flow sensor is not sending enough signal to wake up the heater or the PC board goes to sleep. Either way, you have to remove the power to get it to reset. When it finally powers up it get "--" and then a "1" as it lights.
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