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Techmar 667 Snowmelt slab too hot


I have a TechMar 667 SnowMelt Controller and a TechMar D423 universal reset module.

When the snowmelt is operating (090 sensor wet) , it seems to run at 100% (maximum heating), regardless of the slab temp.

This morning, both boilers were running at 100% and the slab temp was 47 even though "SLAB TRG" is set to 36.

Any ideas?



  • Zman
    Zman Member Posts: 7,496
    It sounds like you may have a sensor in the wrong place or an incorrect setting.It could also be in the piping.
    I assume you are doing variable speed mixing. What is the output to the circ?
    A picture of the piping would help.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein