Installing Evohome thermostat to Greenstore cyclinder

Good afternoon all,

I'd just like to preface the following post by saying that I'm fully aware that any work completed on an unvented cylinder requires a G3 ticket, and I don't plan to make any modifications to the hardware or the wiring of the cylinder...

My heating consists of a Greenstar 24 ri and Greenstore unvented cylinder in an s-plan system.

I have recently installed the honeywell evohome system, with both zone valves now controlled via the honeywell wireless relays. For the DHW, the original duel stat is untouched and in the lower sensor pocket. The honeywell stat is temporarily fixed in the upper sensor pocket.

Despite posting on several forums no one has been able to provide a good answer on how to permanently (or securely) fix this thermostat. The duel stat is clamped to the pocket housing. Would anyone be able to help with this predicament?

The wireless relay for the DHW valve is connected in series with the existing duel stat. During testing, reducing the temperature on either stat de-energises the valve. The wiring for the duel stat is untouched, i have simply remove the switched live from the programmer to enter the bdr91, with the switched live from that powering the original duel stat which in turn powers BR of the valve.

Many thanks in advance

Can you post a picture of the 2 dry pockets?

Spring clip

Thanks both, please see attached images of the sensor pockets and the thermostat.

Shaun must admit I’m struggling to see how I could use a spring clip to secure?

Shaun is correct - as always. There is a circular clip made especially to do that job. Unf I haven't seen one in a while.

Personally, I'd push it in as far as poss, double it back onto the socket and zip tie it in place.

Piece of thin metal bent like half moon so it pushes on the probe etc