Stand alone without thermostat

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benalla
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Joined: Sun Dec 12, 2021 2:45 pm

Stand alone without thermostat

Post by benalla »

Hi all,

I have a Vaillant hrExclusief VHR 35C, using it with a Toon thermostat.
The last months I started using HomeAssistant.

Now I want to remove my thermostat, and use something else which can be placed out of sight.
For controlling (on/off ) HA will be used.
I have temp sensors which can be used to maintain the right temperature.

Is OTGW something what I van use?
Can someone help me getting started?

Thanks in advance!
Dipapi
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Joined: Tue Nov 23, 2021 8:33 pm

Re: Stand alone without thermostat

Post by Dipapi »

Hi,

You certainly could, though it's not recommended. You will need to build your own controller. Provided your boiler supports opentherm, you would need to give your boiler a setpoint for the temperature of the hot water that flows through your radiators/heaters. Since just turning on the heat (meaning for example a CS command to heat the boiler to 50 degrees) when you require heating and turning it off again when the room has reached the desired temperature will result in a very large overshoot (i.e. it will heat up the room far beyond the setpoint), you would need to program your own controller, such as a PID. Goal of the controller is to decrease the temperature command to the boiler when the room has almost reached its setpoint. It's not straightforward.

More info can be found here: https://otgw.tclcode.com/standalone.html#intro
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