Programable thermostat

Al_16

I have a one pipe steam system and would like to change out the thermostat(honeywell ct87) for a programmable type. So far no luck finding a compatible unit at the local home improvement places or hardware stores. Can someone give me a model to look for? Thanks for the help.

Doug_22

Programable thermostat for steam

Honeywell CT3500. Has 5-1-1 program ability and you will have to set it to '1' for system (gravity or steam).
http://content.honeywell.com/yourhome/ptc-thermostats/CT3500.htm

Boilerpro_3

The Honeywell Chrontotherms work very well

Thier internal logic helps eliminate the typical overshoot when recovering from setback both in steam a gravity hot water converions. They are a commerical grade stat so are more expensive, but worth the extra dollars. Most of my clients opt for them.

Boilerpro

hvacfreak

T8400C

I just replaced my tilted t-87 with this stat. It's not programmable , but it has an adjustable heat cycle rate that seems perfect for my 1 pipe system ( and at 20 dollars it fit my budget). I have a new system this year with a clean boiler , insulation , balancing , and stat. I have a Chronotherm 4 but it's for a heat pump .

Mark K

Question on the Chronotherm

Hi,

I just installed the Chronotherm IV on my one-pipe steam system. Last night, I turned on the heat for the first time. I had it set for 64 degrees, but it ended up overshooting and the temp went up to 67. I did set the CPH to 1, per the instructions.

Is this normal for this thermostat, and for a steam system?

hvacfreak

Setting of 1 is correct

...it should get better . I had a chronotherm 3 on a hot water system in my old house and I seem to remember it overshooting at times. Think it's thier "Intelligent Recovery " feature.

BillW@honeywell

New VisionPro 8000...

is good for steam, if you want a programmable. The FocusPro is non programmable, but may be a better stat for a 1 pipe steam system. Setting back steam systems is a controversial issue, the results heavily depend on how fast your home loses heat, since the raidators stay hot long after the boiler shuts down. Neither of these are available at retail, but having a pro install them shouldn't be prohibitive. T8400 is OK too, but has a very small display, and is kind of hard to read, compared with the huge display on the FocusPro.

BillW@honeywell

It takes 3 days...

for the Chronotherm to "learn" what your home's heat loss is like. A 1 pipe may very well overshoot after coming out of a deep setback, try to use a 5 degree setback as a starting point. Steam systems emit heat long after the boiler has shut down, that "flywheel" effect may be what you are experiencing.

Doug_22

thermostat

Another one is the Honeywell CT3500 for about $50: http://www.honeywell-thermostat.com/honeywell/ct3500-thermostat.htm

Novice

Thermostat Gone Crazy Hot Water Radiator

It seems my gas boiler that heats my hot water radiator system will switch On when the digital thermostat indicates a tempature drop. Problem is it will not turn OFF when the temperature rises. Last night I was awakend by loud knocking. Went down to the boiler and enmergency water valve was virtually gushing water. Noticed some cold some hot radiators. I think the emergenbcy valve burned off super heated/pressurized water. IS this as simple as replacing igital thermostat?