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Boiler doesn't switch off when CH setpoint is set to 10°C
Posted: Fri Jan 03, 2020 12:40 pm
by iamkarlson
Hi,
I'm using OTGW together with Home Assistant and most of the things work great. However, I have scheduled switching off the heating in the house. I'm trying to get my boiler stop working with setting the temperature to 10°C. Nonetheless, when this temperature is set my boiler displays 40°C on the screen and pump is still working (I hear water going in pipes). Is there any command in OTGW which can just switch off the boiler completely? I've also tried to set modulation level to zero but it doesn't switch off the pump.
Re: Boiler doesn't switch off when CH setpoint is set to 10°C
Posted: Fri Jan 03, 2020 2:19 pm
by hvxl
Please clarify what you mean by CH setpoint?
- Max CH water setpoint (SH command)
- Control setpoint (CS command)
- Room setpoint (TT or TC command)
Re: Boiler doesn't switch off when CH setpoint is set to 10°C
Posted: Fri Jan 03, 2020 3:34 pm
by iamkarlson
Hi hvxl,
I'm setting control setpoint (CS command). Shall I use SH command instead?
Re: Boiler doesn't switch off when CH setpoint is set to 10°C
Posted: Fri Jan 03, 2020 4:32 pm
by hvxl
iamkarlson wrote:Shall I use SH command instead?
I didn't say that.
In combination with CS, there's the CH command to manipulate the CH enable status bit. That bit normally translates into the boiler running the pump.
Note: The boiler usually keeps the pump running for a short while (about a minute) after the CH enable bit is cleared.
Re: Boiler doesn't switch off when CH setpoint is set to 10°C
Posted: Fri Jan 03, 2020 11:08 pm
by iamkarlson
I'm not sure that I'm getting this right but CH=0 then should switch off the boiler. Is this correct? But from documentation is also you can find that if you specify CS by something other than 0 it will send CH=1 automatically. Woudn't be a conflict then? Could you please help me figure out how to properly switch the boiler and don't let my thermostat to control the temperature?
Re: Boiler doesn't switch off when CH setpoint is set to 10°C
Posted: Sun Jan 05, 2020 12:03 pm
by hvxl
You might have a point if the bit were stored in concrete. But it's not, it is stored in RAM. So it's not a big deal to clear the bit when it is set.
The documentation says: "By default the CH enable bit is set after a CS command with a value other than 0. With the CH=0 and CH=1 commands, the bit can be manipulated." Here, "By default" means: Unless you change it with the CH command.
Or were you referring to the page on stand-alone operation? That page describes how to use the OTGW without a thermostat. You are using a thermostat, so that page doesn't really apply for you. Nonetheless I will think about changing the wording to deter people who enjoy finding fault with the provided information.