Switch on

This Forum is about the Opentherm gateway (OTG) from Schelte

Moderator: hvxl

Switch on

Postby djdehaan » Wed Oct 19, 2016 12:49 pm

Hi,
I have the OTGW connected to a Pi, included in Domoticz, for a while, and it works perfect. I currently:
-read activity
-set outside temp
-set room reference temp (thermostaat is in the living)

Now I would like to also use it to control the heating of the upper floors, For that I have to overrule the thermostaat in the living, and have the CV in heating mode while the real temp in the living is above the reference temp. As I can control the waterflow in the living, I can switch on the CV but keep the pump off. In that way, the upper floors will get warmer and the living wont.

How do I set the CV to Go heating?
I tried to swhich CV_active to ON, but that will go off again in a few seconds.
I tried to swicht CV_active, CV_enabled and FlameON all to ON, but they all will go off again in a few sec.
Is there a way to do this?

Regards,
DJ
djdehaan
Starting Member
Starting Member
 
Posts: 3
Joined: October 2016

Re: Switch on

Postby hvxl » Wed Oct 19, 2016 2:28 pm

The items you mention are all status flags from the boiler. Possibly Domoticz allows you to set those, but the OpenTherm protocol does not support that, and neither does the OTGW. So with the next status report the flags will get their real value again.

Opentherm is used with modulating boilers. Contrary to boilers with on/off control, modulating boilers don't just have a simple on state. You have to tell the boiler how much "on" you want it to be. The way to do that with the OTGW is via the CS command. I don't know if or how the CS command is implemented in Domoticz.
Schelte
hvxl
Senior Member
Senior Member
 
Posts: 1223
Joined: June 2010

Re: Switch on

Postby djdehaan » Wed Oct 19, 2016 3:13 pm

@hvxl: OK, I understand, I believe the CS command is implemented, but as a temperature, not as a modulation %. And I see a similar thing in the doc behind your link:
CS=temperature
Control Setpoint - Manipulate the control setpoint being sent to the boiler. Set to 0 to pass along the value specified by the thermostat.
Example: CS=45.8, CS=0

Is that 45.8 degrees?

-do I set a temperature or a percentage?
-do I set it to 0 to have it operate on the Themostaat downstairs, and
when set to something else the thermostaat is overruled?

Thanks,
DJ
djdehaan
Starting Member
Starting Member
 
Posts: 3
Joined: October 2016

Re: Switch on

Postby hvxl » Thu Oct 20, 2016 2:39 pm

djdehaan wrote:-do I set a temperature or a percentage?
All information you found says that it's a temperature. Then why do you wonder if it's a percentage? It's the desired temperature of the water of the CH system as it leaves the boiler.
djdehaan wrote:-do I set it to 0 to have it operate on the Themostaat downstairs, and when set to something else the thermostaat is overruled?
Correct.
Schelte
hvxl
Senior Member
Senior Member
 
Posts: 1223
Joined: June 2010

Re: Switch on

Postby djdehaan » Thu Oct 20, 2016 3:38 pm

Well, I was confused because of your explanation in the first reply:
Opentherm is used with modulating boilers. Contrary to boilers with on/off control, modulating boilers don't just have a simple on state. You have to tell the boiler how much "on" you want it to be. The way to do that with the OTGW is via the CS command.


I translated the 'how much' to a precentage - also because I can see a modulation percentage in Domoticz. However, I cannot change that.

Thanks for explaining this all!
djdehaan
Starting Member
Starting Member
 
Posts: 3
Joined: October 2016


Return to Opentherm Gateway Forum

Who is online

Users browsing this forum: No registered users and 1 guest