We live in a tri level house in WI. The boiler heats via baseboard on the main and upper floors, but in the lower level the hot water pipes run through the floor itself, basically giving us a heated floor to warm up the lower. This winter, our lower is not really heating at all. Last year, it seemed intermittent. Some days it would come on, others not. The thermostat down in the lower, has no on/off switch...nothing. It's just a Honeywell that shows current temp and temp to set it at. Here is a pic of it: enter image description here

Any ideas why the heat down in the lower will not even engage to turn on? My gut feeling is it is not the thermostat itself, and I'd rather save a trip to the store to attempt to buy the right thermostat then install it, or call in a the heating guy if it is something simple here that I am missing...any comments would be great!

  • Oh, and the way we get any warmth down here in the lower is by doing A) opening the basement door, because our basement is actually very warm when the boiler is running on the cold days and B) we have a fireplace down here, but the lower level is pretty big so the fireplace only does so much...which isn't much heating for the whole space. We have resorted to a space heater as well in a spare bed/office room down there as well.
    – Kyle
    Commented Dec 30, 2016 at 20:09
  • Are there zone valves in this system, or is everything one big zone with one pump? Commented Dec 30, 2016 at 21:46
  • Floor registers, directly above the hot water pipes, would allow cool air from the lower floor to drop to the basement while allowing warm air, from the basement & hot water pipes, to rise into the room. Commented Dec 31, 2016 at 21:29

1 Answer 1


If the bottom floor is radiant in the floor heat then you have a thermostat for that zone only. The thermostat is a Model T87 by Honeywell. Also in this zone there should be a thermostatic valve controlling the water temperature to the slab (floor). I would look for a zone valve for this system. If you can't trouble shoot this your self I would call an HVAC co. to do the work so you don't do something you can't fix.

  • If update your question with more details, and pictures of your boiler, and the zones, this answer can be improved. Commented Jan 11, 2017 at 17:47

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