Home Automation Domotica Forum Europe, Bwired Forum

Posted: **Sun Mar 29, 2015 12:59 pm**

Hi!
Thank's for the hard work on the Opentherm gateway 4.2.3
I got a central heating system with a cm737 Honeywell modulating thermostat.
The Remote override room setpoint don't working with my thermostat, so
I try to use the CS and CH command.

For example if I want to stop the central heating with the
CS=10.00 command the value return to the default 35.00
after about 1 minute.
se my log.

I hope someone could help me..
Regards
Tommy

Code: Select all

1:59:25.746988  T90012300  Write-Data  Control setpoint: 35.00
11:59:25.947970  R10010A00  Write-Data  Control setpoint: 10.00
11:59:25.951947  BD0010A00  Write-Ack   Control setpoint: 10.00
11:59:25.958156  A50012300  Write-Ack   Control setpoint: 35.00
11:59:26.283926  T801A0000  Read-Data   DHW temperature: 0.00
11:59:26.478886  R80010000  Read-Data   Control setpoint: 0.00
11:59:26.482577  BE0010000  Data-Inv    Control setpoint: 0.00
11:59:26.489464  A701A0000  Unk-DataId  DHW temperature: 0.00
11:59:26.820891  T80190000  Read-Data   Boiler water temperature: 0.00
11:59:27.025294  BC0191C28  Read-Ack    Boiler water temperature: 28.16
11:59:27.379735  T00000300  Read-Data   Status: 00000011 00000000
11:59:27.580006  BC0000300  Read-Ack    Status: 00000011 00000000
11:59:27.915894  T00000300  Read-Data   Status: 00000011 00000000
11:59:28.117163  BC000030A  Read-Ack    Status: 00000011 00001010
11:59:28.512606  T00000300  Read-Data   Status: 00000011 00000000
11:59:28.813309  BC000030A  Read-Ack    Status: 00000011 00001010
11:59:29.014010  T00000300  Read-Data   Status: 00000011 00000000
11:59:29.216332  BC000030A  Read-Ack    Status: 00000011 00001010
11:59:29.520243  T00000300  Read-Data   Status: 00000011 00000000
11:59:29.721128  BC000030A  Read-Ack    Status: 00000011 00001010
11:59:30.056332  T00000300  Read-Data   Status: 00000011 00000000
11:59:30.262669  BC000030A  Read-Ack    Status: 00000011 00001010
11:59:30.590028  T90012300  Write-Data  Control setpoint: 35.00
11:59:30.791125  B50012300  Write-Ack   Control setpoint: 35.00

Posted: **Sun Mar 29, 2015 10:39 pm**

Posted: **Mon Mar 30, 2015 11:22 am**

It's working!

case closed!

Regards
Tommy

Posted: **Sun Feb 14, 2021 1:44 pm**

Hej,

I hope it is ok to lift this old topic up again. I have the same Cm737 and figured as well, a bit disappointingly, that remote override room set-point doesn't work.

No, if I understand correctly, one could try to set the control setpoint (aka boiler water set-point?) and or central heating enable to lower the heating remotely instead (and I have read the warnings on tgw.tclcode.com).

What I want to understand is, how setting the control setpoint and the relative modulation level play together. Is the thermostat setting the boiler temperatur or the modulation level? If I set the control setpoint, is the boiler then adapting the modulation level? Or does using CS= means that boiler control will be on-off instead?

And then, in this topic earlier, how to I reverse whatever change I make with DA=1? With AA=1? But why?

Posted: **Sun Feb 14, 2021 10:52 pm**

The Opentherm protocol defines two parameters for the thermostat to control the boiler: The control setpoint (MsgID 1) and the Max relative modulation (MsgID 14).

Depending on the situation, a thermostat will normally control the boiler using one of the two parameters, while setting the other to its maximum. For example: When the room temperature needs to be raised from 16 to 20, the thermostat allows the boiler to use whatever modulation level it needs (MsgID 14 = 100%) to achieve a requested water temperature (specified in MsgID 1). On the other hand, to maintain a certain room temperature, the thermostat may tell the boiler to run at its lowest modulation level (MsgID 14 = 0%), heating the water to whatever temperature (MsgID 1 = 80°). So, you can see a mix of the two methods with a single thermostat.

You got the DA/AA thing backwards. The DA=1 command was suggested to reverse the change that was made via an AA=1 command. Running DA=1 on a normal OTGW will do nothing. So there is nothing to reverse. Furthermore, the problem that happened due to the AA=1 command has been fixed in firmware version 5.0.

Posted: **Fri Mar 05, 2021 9:27 pm**

Thanks again for this. I have now logged my heater and see that Max relative modulation is always 100, it is only the control setpoint that changes. So I can assume that the thermostat only steers by the control setpoint, right?

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