Replace old Honeywell controller and wireless thermostat with Tado! Help!

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trivialgale
trivialgale ✭
in General Questions & Topics

Hi there,

I have recently moved in to a property with an old Potterton 60EL boiler and a Honeywell ST499A/ST699B Central heating controller. The setup also includes a Honeywell wireless thermostat model number DT92E (I believe). This includes a thermostat control and a relay box BDR91 that is connected to the central heating wiring.

I am trying to install a Tado wireless temperature sensor, wireless receiver and internet bridge as included in the wireless starter kit. When installing the wireless receiver I have found options to install to replace either the Honeywell ST499A/ST699B Central heating controller or the Honeywell wireless thermostat DT92E not both. I’m fairly sure one of these needs replacing and the other removing entirely but not sure which one and how to do it.

Does anyone have any installation experience or advice with this setup? Pictures attached show the products in question and a general overview of my heating system.

 

BDR91.jpg
General.jpg
ST499A_ST699B controller.jpg
Wireless thermostat.jpg

Many thanks.

Comments

  • trivialgale
    trivialgale ✭
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    I’ve taken a photo of the wiring behind the BDR91 and have added it
  • johnnyp78
    johnnyp78 ✭✭✭
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    you appear to have a wiring junction box in there. If you just want to replace heating you could put a wireless receiver in place of the bdr91. If you want hot water control as well it looks like it might take a bit of rewiring.
  • wateroakley
    wateroakley ✭✭✭
    edited November 2023
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    @trivialgale this is straightforward. Replace the ancient Honeywell CH and HW slider control with the wireless receiver from a tado wireless starter kit. The backplate of the old room stat receiver will need to link across the two wires going A and B, using one of the supplied links in the Tado kit.

  • trivialgale
    trivialgale ✭
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    @wateroakley thanks for replying. Do you mean I should link A and B with a wago connector and do I need the N and L connections or should i remove?
  • wateroakley
    wateroakley ✭✭✭
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    When you have bought your kit, reach out to Tado and they should give you wiring instructions.

    Looking at what you have, i'd say link A and B (eg with a Wago connector). L and N wont be needed, just make sure everything is safely terminated (eg leave them alone). If in any doubt, reach out to a professional.

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