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Rinnai error code 12

rreale Member Posts: 1
edited February 2021 in Gas Heating

I have been getting error 12 intermittently for a few months. I took out the thermopile (manual calls it a thermocouple, but it has 2 wires that plug into the circuit board), and cleaned it. helped the first time , but not any more. When the unit is running(flame is on) my voltmeter shows approx 19 millivolts from thermopile. Is that enough. The unit is a Rinnai RCE-329a Natural gas ventless heater. The part I tested is RC-511-66-1. I believe this part was used in some of their older tankless water heaters. If you think i need a new thermopile, any idea of one that will fit. Rinnai no longer makes this part, and i cant find it. thx


  • HomerJSmith
    HomerJSmith Member Posts: 2,266
    It is probably a thermocouple and not a thermopile. The voltages between the two are vastly different. I would expect Rinnai to know what they are talking about. A thermocouple puts out about 30mv.

    You might have to jury rig a solution. Call Rinnai and ask them what they think. Talk to technical or engineering.
  • rreale
    rreale Member Posts: 1
    well, it doesnt have the copper sleeve that thermocouples generally have. it has 2 wires. I will try rinnai again, but the last time i tried they pushed me to a dealer, that says the part isnt made anymore or just doesnt call me back. johnstone supply and fw webb doesnt have anything close.
  • rreale
    rreale Member Posts: 1
    I called rinnai, they said it should it should throw 18 millivots. When i tested it threw 18-19, so it appears good. He said i needed to adjust the gas pressure. the manual states how to do this, but i dont have the proper tool to do this. Trying to find someone to work on it , is not easy