The Efficient Home Forum

Evotouch, S Plan system, 2 Heating Zones controlled by 2 wireless thermostats (Y87Rf2024) and relay boxes, HW controlled by ATF500DHW, Oil Condensing Boiler.

Is there a simple way to add better control of the boiler and pump which at the moment runs on/off on the Zone Valves Orange wires?

Thanks

Well evohome was never designed to operate zone valves and switch live onto the boiler, so this was always a compromise.

Best way to do this is NO ORANGE WIRES WHATSOEVER... So a BDR91 controlling the oil boiler and primary heating pump directly (setup as a heating relay), Hot Water BDR91 controlling the opening and closing of the hot water motorised zone valve and then the relevant BDR91's attached to the relevant heating zone valves.

I have set up the S plan with zone valves. Works fine except when I call for heat the hot water valve is opened also, even though the hot water is OFF

wghurley wrote:I have set up the S plan with zone valves. Works fine except when I call for heat the hot water valve is opened also, even though the hot water is OFF

Yep, like I said above, the core design of evohome when using HR91/HR92 Radiator Controllers was never to be used with zone valves on the heating pipework. If you look at PDF page 48 of the evohome Installation Guide (https://thesmartthermostatshop.co.uk/in ... tachment=7) you can see there is no zone valve fitted to the heating flow when fitting HR91 or HR92 Radiator Controllers to all radiators.