Single Pipe Steam heating-What thermostats are you using?

HenryT

Hi, trying to get an idea of what is the best thermostat to use for single pipe steam heating for a residential home.

I am currently using a 7+2 honeywell programmable thermostat. I suspect that the stated temperature is not right. It lists 69 degrees but the house feels chilly.

FJL

T-Stat

Honeywell Vision Pro TH8000 series.  I use it in my building, which is a four unit building, with a sensor in one apt.  Works well for us.



Do you have a thermometer in your residence?  There are times when my thermometer reads 68 or 69 and I feel chilly.  

jpf321

comfort varies .. however ...

my wife and I found that 69 is chilly and 70 seems just right .. go figure. 

Jean-David Beyer

If I walk up to you and ask you what the temperature is, ...

and you had not recently examined a thermometer, you might be within 5 degrees of being correct. If you play this game a lot, you might be within three degrees. On the other hand, without your knowing the room air temperature, if I change it one degree, you would very probably notice it.



So I am not surprised by your observation.

jpf321

F & C

well it's a good thing we live in the US with that very high resolution F scale .. if we lived another place and changed it 1degC we might be too hot or very chilly :-)

crash2009

We both like 69

Seriously though, I am just using one of those cheapo round Honeywell's CT87's.  There are 3 models,  call Honeywell find out the right one for steam 1-800-468-1502.  Out of the box it is set for forced air and had to be adjusted for steam.  I think I have it to set it to 1.2 cycles/hour, the lowest setting.  I needed a magnifying glass to see the settings.  It seems to be working ok.  I set it at 69 three years ago, and only turn it up when flushing or skimming. 

TomM

-

still pondering getting one of these:

haaljo

I use a fancy Tstat by honey but only use

the setback feauture, The aniticipator  functions have been disabled as they defeat deep setback purpose. The important thing for me is that it is battery operated as I have a millivolt standng pilot boiler...........and it makes installation a lot easier and it has a lot of batteries so don't have to replace for awhile. It cost about $100. Just amazing what you can get for $100 in  house controls.

haaljo

Conshohocken PA? muist be a good story on that

control device. Amish or Mennonite?

Polycarp

Honeywell

I have (what I assume is) the same Honeywell on both hot water and steam radiator systems.  I've been pleased with them.  However, I have found that with almost all thermostats, the temperature should be taken as a relative rather than absolute reading.  68 degrees is not necessarily 68 degrees, but it is 1 degree warmer than 67 degrees.



Radiant mass is one of the biggest reasons for this.  Most T-stats take their reading off of the air temperature.  However, our perception of temperature is heavily influenced much more by the temperature of the surfaces around us and not just the temperature of the air.  Therefore, if the walls, ceiling and floor are cold, you can feel cold even in a room with a higher air temperature. 

jpf321

have i heard correctly that ....

there is a honeywell, perhaps, that actually takes it's reading from the wall it's mounted on? that would perhaps support polycarp's comment. 

Polycarp

air v. wall

Even the air-based t-stats will be influenced by wall temperature if only because the wall temp affects the air temp around the t-stat.



One potential pitfall of using wall temperature is that which wall the t-stat is on becomes even more vital. Interior v. exterior walls can be a big difference. In some older homes, the exterior walls may never really warm up, even after the space is considered comfortable.



In the end, you still have a situation where your t-stat is reliable for relative temperature, but not absolute temperature and certainly not comfort.

FJL

Interior vs Exterior Wall

The interior vs exterior wall makes much sense.  I confess that the distinction never crossed my mind.  We installed a sensor in one apartment on an interior wall, but that was just a coincidence.  We used an interior wall only because the wire from the t-stat entered the apartment through an interior wall and we didn't want to lay wire inside the apartment.  I guess if we had put it on an exterior wall, the sensor would be sensing a lower temp and calling for heat more often.  

SteamHeat

Use T-Stat with Adjustable Differential

Using Robertshaw RS6110 with differential set to 3 degrees.



Aprilaire also has adjustable differential upto 3 degrees.



Recommend putting a block of styrofoam underneath Thermostat to isolate wall temperature from sensor.



Hope This Helps

rmoore007ri

Honeywell thermostats

I'm using a Honeywell CT3600 in a 200 year old house. With 1 pipe steam a la Holohan. These thermostats are actually PID controllers - they learn the thermal properties of the house and adapt. If you program 68 dg at 5 am the furnace will come on earlier. So that the house is JUST 68 dg by 5 am. To do this, the thermostat needs to compare the air temperature with something else  . . . in this case the temp of an interior wall. From the manual:

Your CT3600/CT3697 is actually a small computer. The Smart Response technology calculates the correct time of day to turn on your heating or cooling system. Smart Response technology considers the following information.

- Air temperature.

. Wall temperature.

. The time of day when you want the comfort temperature established.



The temperature never drifts up or down by as much as a degree. Unlike most thermostats including simple "digital" thermostats which cycle the house through +/- 2dg.

bob

Jean-David Beyer

they learn the thermal properties of the house and adapt.

I have a Honeywell CT3600 thermostat that has this so-called Smart Recovery. It is connected to my mod|con with outdoor reset that drives in-slab radiant heat. It NEVER learns my house. First of all, the time-lag between when the thermostat calls for heat, and when the temperature of the room changes is just too long. And, because the outside temperature is never the same on different days, it is just beyond the ability of the thermostat to learn anything. My solution here is to do no setbacks.



Upstairs, I have oversized baseboard and a Honeywell TH4110D thermostat with Adaptive Intelligent recovery. It works better than the downstairs, but it too  never really learns the house because of the outdoor reset. Since I do not use the upstairs all that much, I have about 2 degree reset there at night. Depending on the outdoor temperature for the last few days, it sometimes recovers and sometimes does not by the desired time. I think if the outside temperature stays the same for about a week, the thing learns what is going on, but that does not happen all that much around here. When it changes every day, the more usual case, it is ineffective.



My view is that outdoor reset can be effective, but you should give up on setbacks, or if you use them, do not expect much from the intelligent recovery feature.