Help wiring DHW tank insertion sensor unvented tank

[kartingmad]

I am planning to fit Domestic hot water wireless kit as part of an S Plan Plus system, however as the HW tank (range tribune HE) is part of an unvented tank and I want to use the insertion sensor.
I understand that there needs to be a max temp limit cut out, however I'm not sure how to wire this between the Honeywell sensor (supplied in the kit) and the BDR91. The current Insertion sensor (standard fitment to the tank) has a limit cut-out inline, can I use the existing sensor (and limit cut-out) and wire to to the BDR91 or is there another way to achieve the temp protection required.
I'd be very grateful of some advice please - Previous install experience, vented system using the strap on sensor (not possible on this double insulated tank).

[Fishtank]

I'm also in the same situation as you, hopefully someone with the knowledge will respond.

[lloyd]

The over temp limit stat needs to operate independently of evohome. I think the correct way to wire it is in series with the switch contacts of the bdr91.

Do not wire it in series with the evohome temperature probe.

[kartingmad]

UPDATE !
I contacted Honeywell Tech Support (very helpful), who confirmed that you leave the original insertion sensor (originally fitted to the tank) in the insertion sensor and wire the switch (brown) wire to the motorised valve in series through the limit sensor. This means that if the temp raises too high in the tank, that the limit sensor will cut supply to the motorised valve - I also wired through the original tank stat (just because it was much easier ) and turned that up to max. I was then able to check it was working by turning the original tank stat down when the HW was running.
The Honeywell insertion sensor went into the same pocket behind the original, so both insertion sensors in the same pocket. The Honeywell sensor wired to receiver as normal.

[Richard]

UPDATE !
I contacted Honeywell Tech Support (very helpful), who confirmed that you leave the original insertion sensor (originally fitted to the tank) in the insertion sensor and wire the switch (brown) wire to the motorised valve in series through the limit sensor. This means that if the temp raises too high in the tank, that the limit sensor will cut supply to the motorised valve - I also wired through the original tank stat (just because it was much easier ) and turned that up to max. I was then able to check it was working by turning the original tank stat down when the HW was running.
The Honeywell insertion sensor went into the same pocket behind the original, so both insertion sensors in the same pocket. The Honeywell sensor wired to receiver as normal.

Just to state that although Resideo have given you a solution, G3 regulations do apply to unvented cylinders so only competent heating installers should be doing these works (unless you can show you are fully component to check the safety systems after the modification of the works on the cylinder, but this normally requires a BPEC or equivalent qualification for domestic hot water systems, which is very different to dealing with a vented cylinder).

[Fishtank]

Thanks kartingmad.