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TEKMAR mated to IBC boiler - Conflict?

YukonerYukoner Member Posts: 6
edited December 2019 in Controls
Hi there
I live in Yukon and have radiant floor heating in a lightweight concrete slab. My Tekmar 361 controller is about 18 years old and has performed flawlessly. I recently changed from a Weil McLain Gold oil-fired boiler to an IBC , model SL10-85 G3, propane boiler. My heating system is basically like this:

The boiler is doing a fine job of keeping the high temp loop hot. But the injection pump is not pumping into the low temperature loop, even though I raise the desired room temperature on the Tekmar.

I thought the injection pump was toast and had a plumber come in to replace it today, but still no joy. The only time I can get the pump to work is by turning the breaker off and then on - the variable speed indicator slowly climbs: 10%, 30%, 50%, 70% (feeling some heat in the pipe for a few seconds), 90% (pipe is very hot for a few seconds), then the burner icon comes on, the percentages quickly drop to nothing, and the pump shuts down and the pipe cools off again. This all happens in about a minute.

With the old boiler, the burner icon (boiler relay indicator) on the Tekmar would come on when the high temperature loop temperature fell below a set threshold and would turn on the boiler. Since the changeover to the IBC boiler, the burner icon on the Tekmar control is ALWAYS on. The old WM boiler didn't have a brain - it just did what the Tekmar controller told it to do. But the IBC boiler has it's own controls built in. I suspect that it has some kind of conflict with the Tekmar controller.

Any ideas? I have feelers out, but it's hard to find anyone up here with Tekmar knowledge.



  • kcoppkcopp Member Posts: 3,523
    You no longer need the tekmar. Part of the reason for the injection was to protect the boiler. The new boiler can handle the lower water temps and actually wants to condense. Pipe the boiler w/ the primary loop then pipe the radiant off that primary loop. Hook the T-stat directly into the boiler.
  • ZmanZman Member Posts: 5,921
    The tekmar was originally installed to provide outdoor reset to the slabs and protect the original boiler from condensing water temps.
    The new boiler loves condensing temps and runs more efficiently at them. It is also capable of managing outdoor reset by varying the internal target temps.
    Whoever replaced the boiler without removing the tekmar just plain "does not get it".
    I would repipe the boiler per manufactures instructions, set the outdoor curve, and be done with it.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • YukonerYukoner Member Posts: 6
    Thanks for the replies, guys. The system also includes a Kitec manifold.

    Okay, you both are saying that I can eliminate the Tekmar controller. It's redundant. Makes sense.
    So the piping should be redone so that the boiler output simply feeds directly into the bottom of the manifold, eliminating all the extraneous injection piping and injection pump?
    Is it okay to have two pumps running in series? The black pump from the high temp loop would be feeding the manifold, from the boiler. But there is also the existing pump inside the manifold (which runs constantly, circulating water throughout all the floor loops). I'm thinking this one is a stronger pump, as it's pumping through 11 300ft loops. It's a Grundfos UP26-99F, 2.5A. The high temp loop pump is a Grundfos UP15-42, 0.74A.
  • ZmanZman Member Posts: 5,921
    You want to pipe it primary/secondary as the manual directs. There will then be no high temp loop. How is your domestic water heated?

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Member Posts: 13,680
    or a sep with 4 functions in a single component..
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • YukonerYukoner Member Posts: 6
    Okay, that's pretty much what I figured you meant. DHW is just electric at this point.
  • YukonerYukoner Member Posts: 6
    Thanks for the enlightenment, guys. Your advice subsequently lead to me getting a really bright plumbing /heating guy over and he agreed 100% that the Tekmar was now redundant on my system. The piping has been simplified and my system is working like a charm. We'll just be doing some fine tuning over the winter to get the heating curve dialed in. The primary loop is not high temp like it was with the old system, so I'm sure I'll be saving some money on fuel from now on. And it was good timing too, as we have had a cold snap for the past couple of weeks, down to -40 on some days. That doesn't include wind chill. Nice weather for penguins. Just warmed up today to a balmy -20C (but -34 with the wind chill).
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