Of course, the subjecttitle of this topic does not quite well slice it...
I'm looking for a thermostat which support the following features:
must have:
- (some sort of) tele-contact
- it must accept a setpoint to 0.1 degree accuracy
- it must be able to perfectly communicate with the OTGW
nice to have:
- a display which show outside temperature, room temp and room setpoint.
-
I now own a Honeywell Touch modulation, but this thermostat has the looks, but it ignores the accurate setpoints I feed it with. OTGW accepts the accurate setpoints but the thermostat rounds it to .5 degrees.
Which thermostat accepts 0.1 degr accurate setpoints?
Moderator: hvxl
Re: Which thermostat accepts 0.1 degr accurate setpoints?
What exactly do you mean with "must accept a setpoint to 0.1 degree accuracy"?
The Remeha iSense accepts setpoints with 0.1 degrees resolution. I.e. after sending a TT=18.68 command, it comes back with a room setpoint of 18.60 (apparently is doesn't round the number up). On the thermostat itself you can only adjust the setpoint by 0.5 degrees, so after setting the setpoint to 18.6 you can only manually change it to 19.1, 19.6, etc.
The Honeywell Chronotherm Modulation even accepts setpoints with 0.01 degrees resolution. However, it always shows the setpoint rounded to .5 degrees on its display.
Going slightly outside your requirements, the Remeha Celcia 20 accepts setpoints with a resolution of 0.2 degrees.
What do you want to use the tele-contact for? Even if they do have a tele-contact, many thermostats don't support remote setpoint override via opentherm and a tele-contact at the same time. You have to configure which one you want to use. The OTGW provides a feature similar to the tele-contact functionality of a thermostat via its GPIO pins. The Honeywell Chronotherm Modulation has a tele-contact that will work together with a remote setpoint override via opentherm.
All three thermostats I mentioned can show outside temperature, room temperature and room setpoint on their display, albeit not all at the same time. You have to push some buttons to get at all the information. All of them communicate fine with the OTGW.
Unfortunately the Honeywell Chronotherm Modulation and Remeha Celcia 20 are not produced anymore. You probably need to look on Marktplaats or eBay to be able to get one of those.
Note: I'm not implying these are the only thermostats that (sort of) fit your requirements. They are just the only ones I can comment on with a reasonable level of confidence.
The Remeha iSense accepts setpoints with 0.1 degrees resolution. I.e. after sending a TT=18.68 command, it comes back with a room setpoint of 18.60 (apparently is doesn't round the number up). On the thermostat itself you can only adjust the setpoint by 0.5 degrees, so after setting the setpoint to 18.6 you can only manually change it to 19.1, 19.6, etc.
The Honeywell Chronotherm Modulation even accepts setpoints with 0.01 degrees resolution. However, it always shows the setpoint rounded to .5 degrees on its display.
Going slightly outside your requirements, the Remeha Celcia 20 accepts setpoints with a resolution of 0.2 degrees.
What do you want to use the tele-contact for? Even if they do have a tele-contact, many thermostats don't support remote setpoint override via opentherm and a tele-contact at the same time. You have to configure which one you want to use. The OTGW provides a feature similar to the tele-contact functionality of a thermostat via its GPIO pins. The Honeywell Chronotherm Modulation has a tele-contact that will work together with a remote setpoint override via opentherm.
All three thermostats I mentioned can show outside temperature, room temperature and room setpoint on their display, albeit not all at the same time. You have to push some buttons to get at all the information. All of them communicate fine with the OTGW.
Unfortunately the Honeywell Chronotherm Modulation and Remeha Celcia 20 are not produced anymore. You probably need to look on Marktplaats or eBay to be able to get one of those.
Note: I'm not implying these are the only thermostats that (sort of) fit your requirements. They are just the only ones I can comment on with a reasonable level of confidence.
Schelte
Re: Which thermostat accepts 0.1 degr accurate setpoints?
Thanks Schelte.
It seems that the Honeywell Chronotherm modulation does the job, so I just bought one on marktplaats.
If the room setpoint is .5 degrees higher than the room temperature, the Elga goes full power. However, if you stay between 0.1 and 0.4 degrees, it instructs the Carrier xPower to a setpoint a bit lower.
Right now, with the Chronotherm Touch I have two options: full power or no power. So actually, I would like a more fine-grained control over the Elga's power. With the "good old" Chronotherm Modulation/Gateway/Netduino, that's the easiest way for now.
In a later stage, I could use the interface firmware and get rid of of the thermostats.
It seems that the Honeywell Chronotherm modulation does the job, so I just bought one on marktplaats.
If the room setpoint is .5 degrees higher than the room temperature, the Elga goes full power. However, if you stay between 0.1 and 0.4 degrees, it instructs the Carrier xPower to a setpoint a bit lower.
Right now, with the Chronotherm Touch I have two options: full power or no power. So actually, I would like a more fine-grained control over the Elga's power. With the "good old" Chronotherm Modulation/Gateway/Netduino, that's the easiest way for now.
In a later stage, I could use the interface firmware and get rid of of the thermostats.
Re: Which thermostat accepts 0.1 degr accurate setpoints?
I just realized there may have been several models that were all referred to as "Honeywell Chronotherm Modulation". My remarks were for the CMT8851M1000. I hope that's the one you bought.
Schelte