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which outdoor reset control to use?????

frank s
frank s Member Posts: 64
I am installing my first radiant job, in a big 900 sq.ft bonus room ( remember me Dan?) The homeowner would like an outdoor reset control to control not only the radiant zone ,but also the high temp zones, which are existing...2 hydro airs and DHW tank. If you can keep it simple and as inexpensive as possible. Thanks, and a special thanks to Chris M. at Thames Valley Winnelson for all his design help. Your opinions and advice are greatly appreciated.
Frankie Sev


  • Jamie Pompetti
    Jamie Pompetti Member Posts: 82


    Can you fill us in on what type of radiant system you are installing? Injection or Mixing valve? I found out the hard way that if you are using injection it's better to reset the radiant and let the boiler do its own job(run @ higher temps / 160 and up). But if using mixing valves you can reset the system (meaning boiler temp too).

  • Boilerpro
    Boilerpro Member Posts: 410
    I've done this

    Not sure what boiler you have, but if you want full reset, you may need to use a variable speed pump system , or a return mixing valve on the boiler (ala. Danfoss/ Esbe Thermix valve) for boiler return temp protection and then pipe the system Primary/ Secondary. Take the high temp loops right off the reset supply water. For the low temp loops use a seperate pump and a fixed mixing valve (about 20$) to provide a fixed amount of supply water to mix with a fixed amount of return water. By doing this the supply temp to the low temp part of the system is reset right along with the high temp part. Simple, inexpensive and very effective. I use tekmar controls and if using a mixing pump, I'd go for the 361 (it has additional relays and doesnt't require a transformer like the less expensive 356). If a condensing boiler is used, or you only plan on partial reset, a 256 may be all you need. The big mechanical contractors in my area still can't figure out how this works, Oh well more work for me. And that's my two cents for what its worth.

  • heatboy
    heatboy Member Posts: 1,468
    Wirsbo 311............

    would be a good choice. Full reset for the radiant via mixing valve or VSI. Partial boiler reset on the coils would greatly increase comfort and add a 10K sensor to the indirect and control that from the 311 also. Nice package.

    Warm Regards,


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  • frank s
    frank s Member Posts: 64
    floor type

    I'm using 1/2" pex,12"O.C. using the sandwich method, pump and 3 way valve, and wirsbo promix 101, I was trying to find some literature on the 311 but wasa unable to find anything on the wirsbo site, thanks Frank
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