I have a ground source heat pump (econar 5T unit) being driven by a Tekmar 262 boiler control. The heat pump has anti-short-cycling protection built in; if the heat pump demand signal is turned off before some minimum run time, the heat pump lights up an anti-short-cycle warning light, which turns off 90 seconds later. Unfortunately, the documentation does not say what that minimum run time is. I have experimentally determined that it is something greater than 10 minutes.

The tekmar 262 manual claims it honors some kind of minimum boiler run time, but no-where in the settings or manual can I find a minimum run time setting. So how do I get it to honor whatever minimum run-time I want? Right now it is turning off the boiler (heat pump) signal whenever it loses a hot-water demand signal.

  • Have you considered contacting Tekmar to ask them? Might be the simplest, most direct, most accurate way of getting the answer.
    – FreeMan
    Commented Jan 9, 2023 at 16:58
  • Seemingly it just works when you ask it to do so, thus no minimum run time needed
    – Traveler
    Commented Jan 9, 2023 at 18:37
  • @FreeMan Yes, I've contacted Tekmar and they just sent me exerpts from the installation manual which I already have. Says nothing useful in terms of the actual time. Commented Jan 12, 2023 at 17:57
  • @Ruskes No, it doesn't "just work". If told to start too soon, it shuts off permanently in a lock-out condition and has to be powered off for at least a minute before being repowered. Commented Jan 12, 2023 at 17:58
  • It appears that the red ASC lockout light turns on whenever the unit is "turned off", i.e. the activation contacts to produce heat are opened. If no "turn on" signal is received for the next ~90 seconds, the ASC lockout light is turned off and the unit will turn back on (start producing heat) when the activation circuit is closed. Commented Jan 12, 2023 at 18:04


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