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Tekmar 265 boiler sensor location?

Heating system is a Biasi boiler with an indirect. Home uses combination of fin tube and cast iron radiation. There is a 113 degree ESBE TV valve on the boiler. There are three zones with circulators. The heating loop is Primary-Secondary. Indirect is directly piped through the boiler.

Where is the best place to mount the Tekmar sensor for the boiler temperature? Directly at the boiler, or
at the port on the TV valve that feeds the heating the system? Right now it is mounted direct to the
boiler, but that temperature is regulated by the TV valve bypass. Either sensor location will show the
Tekmar the exact boiler water temperature for DHW, but the location will affect how the Tekmar senses a heat call.


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    edited December 2019
    Why 113° for a bypass?

    A simple sketch would help.
    Without seeing your piping, it should probably be right passed the bypass, on the pipe supplying heating to the zones and the DHW.
    It's more important to have it monitor what is going to the zones rather than the indirect as when a call for the indirect occurs, it's going to reset the supply target to DHW exchange setting, which will most likely never reach the sensor while recharging your indirect.
    I assume you have an aquastat on the boiler to detect temperature and shut off if it reaches the high limit setting.
    And an aquastat on your indirect tank.