Looking for programmable thermostat for radiant heating

scrook_2

Why not get/use a conventional, programmable t-stat but set it for hot air cycle rate not hydronic cycle rate -- that'll tighten the differential (to achieve the shorter cycle rate -- the two go hand in hand). If the ABSOLUTE accuracy is off (though this shouldn't be important for this application, just repeatability) then set it to read a degree (or 2) higher or lower, as req'd.

Use outdoor reset too, of course, so the system's not prone to overshooting or short cycling, as without correctly set ODR, short cycling must also go hand in hand w/ tight differential.

Tom Hopkins

Hi all. I have been reading this forum for a few weeks. Thanks to all the professionals who contribute their time.

I am looking for programmable thermostat for hydronic radiant heating for a customer. He finds that his digital thermostat is not accurate enough.(There is a 2 degrees diffetrential)

I have a hard time to find what he wants.
A precision of about 1 F (plus/minus 0.5 degree celcius), programmable, without batteries(powered by the 24V) and that has a porportional adaptive mode that protects against short cycles.


Any reccommendation?

Thanks,
Luc

scrook_2

tighten differential

Why not get/use a conventional, programmable t-stat but set it for hot air cycle rate not hydronic cycle rate -- that'll tighten the differential (to achieve the shorter cycle rate -- the two go hand in hand). If the ABSOLUTE accuracy is off (though this shouldn't be important for this application, just repeatability) then set it to read a degree (or 2) higher or lower, as req'd. Use ODR too of course, so the system's not prone to overshooting and/or short cycling.

Hvacman

Is there such a thing?

Does accuracy to .5 deg. exist? I can see accuracy like this needed and maintained in a lab or similar environment but I've never been in a home that requires it... Is the customer needing a hobby? :-) Heck, even in some spaces I deal with (archival storage, museums, orchestra hall) we are given a window of +/- 5 deg. and 5% RH.

Mike T., Swampeast MO

Tightest differential I've seen on a thermostat is plus/minus 1F

Tom Hopkins

You are right. My mistake. I sould have mentioned that I was taking about celcius which is about plus/minus 1 F.

Tom Hopkins

Hi Brian,
My mistake I should have mentionned that it was plus/minus 0.5 degrees celcius which is about plus/minus 1F.

In the moment they have a plus/minus 2F on the thermostat and the customer is not satisfied.

kevin coppinger_4

my thoughts...

are that programable/ et back t-stts are not a good match for radiant floor heat...set it and forget about it.

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service guy

Ive installed afull radiant job in my own house & ive found that setting the t-stat back is not cost effective. It takes about 2 hours 4 my system 2 recover from a 2 degree set back. I installed all top of the line stuff buffer tank,outdoor reset the whole 9.
But try explaining that 2a customer!!!!!!!!