w.Intercom = i;img.ProfilePhoto.ProfilePhotoMedium { padding: 10px; }Can't get any hot water if Tado is calling for radiator heat — tado° Community

Can't get any hot water if Tado is calling for radiator heat

macaroon
macaroon ✭
in General Questions & Topics

I've got a Worcester Greenstar Heatslave combi boiler with a wired Tado v3+ thermostat connected via digital (EMS) bus (setting D17).

Hot water is permanently ON in Tado, 24 hours a day, and set to max (65°C).

I've noticed that when Tado is running the central heating (i.e. when a room thermostat calls for heat), my boiler quickly runs out of hot water to the taps. A few times now I've started to run a bath when Tado has coincidentally fired up the central heating.

When this happens the boiler seems to switch from providing hot water to providing heating, and so I'm very quickly left with no hot water and a cold bath!

The key thing here is this did not happen with my previous boiler controller (the boiler's own Worcester programmer). Before Tado, hot water always seemed to trump heating demand and I was able to run hot baths.

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Answers

  • policywonk
    policywonk Volunteer Moderator

    @Emcee This is an EMS /HT specific bus matter. As @Rob is no longer assisting, would you be open to arranging for someone from support to assist @macaroon?

  • Emcee
    Emcee Admin

    Hello @macaroon

    As my colleague Muhammed explained, we would recommend that the hot water zone be deleted from your app. From there, check if everything is working as it should.

  • smeetoo
    smeetoo ✭
    I have this issue too. Did you manage to fix it?
  • smeetoo
    smeetoo ✭
    At the moment, every time I need hot water, I need to turn off the heating on the Tado app.

    Not ideal.
  • policywonk
    policywonk Volunteer Moderator

    @smeetoo Hope you dont mind. The above problem that @Emcee handled was specific to the boiler and configuration which macaroon has in place.

    Is your problem and context identical? If not, would you set up another thread and we'll respond. If it is, please confirm.

  • Jonahs8
    Jonahs8 ✭
    edited March 13

    @macaroon , @smeetoo, I have the same boiler.

    I am just about to physically install my wireless receiver, but having spoken with Worcester, you need to go though the 230v strip, not the 24v. It may be possible via the 24v strip, but I only have the info for the 230v

    According to TADO the WR can not process digital protocols.

    It appears to be the case of wiring into the 230v where the pre-wired links are. These links need removing (circled in red below). Images attached below.

    Please also note the setup in the TADO WR in the first image, because we are also needing to control the DHW, we need to use the purple linking wire to supply switched live power. (The regular instructions (see fig.3 below) for a combi boiler do not have this set up as the regular setup emits DHW control. IF the combi boiler had DHW control separate to the facia mounted control panel, the TADO WR wiring could be done as per the installation sheet (fig.3)

    According to my convo with Worcester, the below should be what's required to replace the facia mounted control unit, running both DCH and DHW via TADO, but please bear in mind I am still to wire mine in to be 100%.

    Screenshot 2025-03-12 110006.png
    Screenshot 2025-03-12 110444.png
    Screenshot 2025-03-13 115319.png
  • smeetoo
    smeetoo ✭
    Thank you! That's very handy. I had given up and gone back to the old controller. Let me know how you get on. Good luck.
  • Jonahs8
    Jonahs8 ✭

    HI Smeetoo, just tagged you before seeing your comment 😅.

    I will post update as soon as installed, with or without frazzled hair and smoke 😋

  • macaroon
    macaroon ✭

    @Jonahs8 Are you sure you have exactly the same boiler and thermostat as me? Because I'm running my setup exclusively through the digital (EMS) bus of the boiler using only two wires. To be clear, I'm using a wired Tado thermostat because the UK wireless versions frustratingly lack digital support. This setup does largely work except for the occasional hot water issue as detailed in my original post.

    @Emcee I'm revisiting this issue a few months later because I hadn't encountered the problem for a while. However last night the problem happened again: the central heating was on (about 0.5°C below target room temperature). I tried to run a bath but quickly ran out of hot water. I turned the heating off via Tado and had to wait 20 minutes until hot water was restored.

    I know your colleague Muhammed advised to delete the hot water zone. Forgive me if I don't understand but wouldn't that leave me with no hot water at all?

    My understanding of what's happening is that the boiler (or Tado?) is diverting all of its heat energy into running the CH and therefore "neglecting" to keep the hot water exchanger at an acceptable temperature. But how would deleting the HW zone from Tado stop that happening?

  • Jonahs8
    Jonahs8 ✭

    @macaroon , sorry, same boiler, not control unit.

    My control unit is the Drayton LP20RF, which connects via a ribbon cable (thus using the 24v supply).

    In order for the Drayton to use the Ribbon cable, or for the EMS ports on the 24v bus bar, the link cables come factory fitted.

    Because I am using the UK version on the WR, I need to go via the 230v switched live option.

    This should / might also be a suitable option for your situation.

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