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New flow sensor for lochinvar combi, red.

cberg
cberg Member Posts: 5
Replaced flow sensor due to dhw calls only, no space heating. Worked good for about 3 weeks, then red light. Anything else that might be the problem?

Comments

  • GGross
    GGross Member Posts: 1,211
    some more info needed, include model of the boiler and a picture of the install if possible. What led up to diagnosing a faulty DHW flow sensor?
  • cberg
    cberg Member Posts: 5
    Lochinvar NKC150N - Had several HVAC techs here, one diagnosis diverter failure..new part, same problem. Another diagnosis, change out connection board...new board, same problem. This heating help forum gave the sensor solution. Changed out sensor, did work but not long term. So whenever I take the sensor off, (not total disconnection just off flow switch) I have space heat. Whenever I reseat the sensor I have only dhw.
  • GGross
    GGross Member Posts: 1,211
    Are you just unplugging the sensor wire? or do you leave the sensor wire attached and remove the flow sensor from the boiler? It certainly sounds like the sensor is reading flow all the time.
  • cberg
    cberg Member Posts: 5
    Leave it all intact, just lifting it off of the flow switch a tad to engage space heat. Then push it down slightly to engage dwh for hot water needed for showers etc.
  • cberg
    cberg Member Posts: 5
    I'm guessing that since the flow sensor is new, maybe the wiring to the sensor could be faulty?
  • cberg
    cberg Member Posts: 5

    Found problem…..flow switch/Transducer

    GGross