Advice on choosing a replacement heat only t-stat

Thermostat?

The thermostat is not your problem. The old mercury stat if you set it to say 70 and assuming it was accurate and the anticipator was set corectly, would let the temp swing from 69 to 72 degrees. That wide swing probably caused the heat to stay on for long periods of time and is what gave you your comfort level. The new digital stat is not allowing that swing causing more frequent shorter cycles.

You have one zone in the house and only one thermostat? I have five stats in my little house. All are digital. I also have a circ fan running. That tends to even things out a bit.

Sometimes..

Sometimes digital stats have a CPH (Cyles Per Hour) setting. You will want to make that as low as possible to mimic the old thermostat. Again, depending on how the old one was working. Sometimes the CPH is called Fuel Type like Oil / Gas What No Coal or wood? I have seen Steam (1 CPH) That might overheat way too much though.

I have a fancy programmable thermostat.

Mine has many cycle time settings.



1  radiant floor heat or gravity steam system

3  hot water system or high efficiency furnace

6  gas or oil forced air heating system

9  electric heat system



My other one has similar settings



1  for steam or gravity systems

3  for hot water systens & furnaces over 90% efficiency

5  for gas or oil furnaces of less than 90% efficiency

9  for electric furnaces.



Note that one says 5 and the other says 6 for lower efficiency furnaces. I assume this means it is not that critical, or not that accurate. The second thermostat can set to 2, 4, 6, 7,10, 11, or 12 as well.



These two are both Honeywell thermostats.



I have two White-Rodgers thermostats that run hot air furnaces. Their cycle rates are in arbitrary numbers. If I remember correctly, they go from about 5 to 40. Higher numbers presumably run slower. I find this confusing, but it is probably usable if yo play around with it.

Floor furnace, heat only digital thermostats.....

I have an old house with a floor furnace. It is controlled by a single thermostat. I would like to replace it with a heat only, non-programable digital thermostat; however, I am having trouble sorting out all the data to find one that is simple, effective and inexpensive. I have looked at the Basic Honeywell PRO 1000 Non-programmable Digital Thermostat but am unsure if it will work on a floor furnance. Any thoughts?



Will this also work as a zone thermostat for a radiant heat system (under hard wood floor)?Thanks.

I wonder what your problem is.

I have a mod|con hot water boiler and two heating zones. Each has a Honeywell thermostat that, for historical reasons are not the same. One zone is radiant slab, and I have it set for one cycle per hour. The other zone has oversized baseboard; oversized so I can run lower temperature water in it. It, too, is set to one cycle per hour. The thermostats I have are fancier than I need, with all manner of fancy setback capability that really make no sense for radiant slab heating. And with large outdoor resets, they make little sense for baseboard .



The thermostat for the radiant zone is a CT3600. I am not sure if it is still available. I could have it run 4 different temperatures each day, for a total of 28 different temperatures. I bought this to save money, but I cannot use it as designed. I did not understand setbacks and radiant slabs. Basically, you cannot do much over 1F setback, and that is not worth the bother.



The baseboard one is a PRO TH4110D. It may still be available. I cannot remember if it is set at 1 or 2 cycles per hour; it can be set for 1, 2, 3, , ..., 12 cycles per hour. For hot water systems, Honeywell recommend 3 cycles per hour, but my boiler runs outdoor reset and I find lowering the cycle rate works better for me.



I use 2F setback at night with this one as I do not use that zone at night. More setback does not work well because of the extreme outdoor reset I use. For example when it is 14F outdoors (design day), I put 130F water into the baseboard. When it is 32F outside, I put 121F water into the baseboard. That is not enough to recover quickly from a greater setback.

Digital tstat

For a basic nice stat, try the honeywell TH-5110d-1006