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Tekmar 351

I have a Tekmar 351 thermostat that needs to be replaced. I would love it for someone to explain how it really works in layman's terms, and what you recommend for a replacement.

Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 5,324
    Signgirl said:

    I have a Tekmar 351 thermostat that needs to be replaced. I would love it for someone to explain how it really works in layman's terms, and what you recommend for a replacement.

    Tekmar never had a thermostat 351. They had an injection mixing control, discontinued. So it’s hard to give advice until I (we) know which component you are referring.
    Take/post some pics.

    steve
    Zman
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,414
    edited November 2020
    The 351 control used an RTU-051 as a thermostat. It is a 2 wire digital devise that communicates with the 351. Not an analog switch that opens and closes.

    If you want to change the thermostats you will need to change the entire controller with something that will operate the injection pump.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • hot_rod
    hot_rod Member Posts: 15,064
    It was a mixing control, had the ability to take an input from a remote sensor as @EdTheHeaterMan mentioned. It was a great control, showed up at a few of the radiant manufacturers offerings.
    Probably early to mid 1990's. Might be time to upgrade.
    tekmar keeps data on obsolete controls at their site.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream