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Buderus gb142

Hoping to get some guidance on domestic hot water control on my Buderus gb142 unit.
When ever it calls for heat the boiler will fire up and run for less than a minute and shut off on over temperature. It continues to repeat that until the water in the holding tank reaches the target temp. This sometimes causes the pressure to increase to above 30 psi and the pressure relief will release.


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Yeah, it’s not working right. Call a competent service company to come out and fix it.

    There was an error rendering this rich post.

  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    I would bet the pump isn't working, which is why it is going off on over temperature.
    It also sounds like the expansion tank might be having an issue also. Need someone competent to look at it.
    delta T
    HVACNUT Member Posts: 5,841
    No codes?