Opentherm with weather compensation

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Dj-999
Posts: 2
Joined: Sat Jan 25, 2025 9:11 am

Opentherm with weather compensation

Post by Dj-999 »

Hi, first post after following the forum for a while.

I currently have a full evohome system with HR92 on every radiator, unvented hot water cylinder with hot water pack controlled by BDR91, opentherm bridge, NO CH zone valve and NC HW zone valve wired X-plan to give hot water priority. The Boiler is an ideal logic system2 S24.

In the quest for maximum efficiency I thought of adding ideals weather compensation kit to work along side opentherm which Ideal say is possible as the boiler will have two temperature settings 80deg with HW demand and modulating with CH demand when the weather compensator is connected.

Currently the boiler has permanent live and only the opentherm bridge wired connections calling for heat and the boiler flow temperature setting overrules maximum demand from the opentherm bridge which is all working as should.

The issue I have is with the weather compensator connected any call for heat from the opentherm bridge the boiler thinks this is a hot water demand.

Ideal haven’t been very helpful but seem to point towards SL1 and SL2 switched lives being required to allow the boiler to differentiate between the demand types. I have also seen a post from Richard showing a link between SL1 in/out which I don’t have but everything is operating with my previous setup.

Has anyone got a similar setup that could point me in the right direction?

Thanks
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