tado c/h causing my baxi 105e boiler to go into fault after every heating cycle

have contacted support , completely ignored the issue ,

after a heating cycle tado causes my boiler to go into fault ,ignition ,

if i reset it will go into another cycle ,and go back into fault ,

if i switch to hot water only , no issues ,tado is not controlling the hot water ,

but if i again go to heating and hot water ,a cycle of heating and we're in fault ,

i've set the target temperature down , so tado has not called for heat ,

guess what, no faults

had Lightwave rf for 6ish yrs before and never had this issue

after contacting support ,and showing the wiring ,

the response was ,Tado is not controlling the hot water, the problem lies elsewhere ?1

anyone else experienced this ?


  • This sounds like the boiler is complaining about an overheating cycle. That may be an issue with the bypass.

  • Are you sure you’ve got it wired up correctly?
  • wired correctly ,if not i may have to give up my job as a sparks

  • Hmmm. What's the make of boiler and is it showing a specific fault code? If you've got the facility to wire it Opentherm/ebus you could try that, see if it makes a difference.

  • sorry just saw you put the make in the title. Doesn't look like it's opentherm/ebus compatible either. You could try resetting the extension kit, or check the contacts. That's all I got I'm afraid.

  • still working with support ,

    gone through the resetting of boiler and wireless receiver ,

    works on call for heat ,so all wiring is fine ,even used ferrules in terminals ,

    and labeled sl and live ,showing pics ,proving continuity,

    last request was what happens if you don't reset the boiler ?,

    well it doesn't work !🤦‍♂️

  • So it’s not the wiring and it’s not the contacts, and it’s not the boiler because it worked with your previous system. I think that leaves two possible answers: 1. All Tado units are not compatible with your model of baxi. 2. Your specific Tado box has a fault that Tado in Germany can’t see.

    Option two would be cheaper to rectify, though annoying as you’ve already shelled out for the kit.
  • after 20 or so emails ,

    i'm trying to get support to choose one of these options ,

    and just take back the 8 x trvs and starter set ,

    and i will go to a different system ,

    lightwave worked fine on the boiler

  • @vespasmurf how many radiators do you have without a TRV fitted?
  • one in the bathroom / towelrail

  • i take it you mean smart trv

  • I mean without any type of TRV. The most likely explanation for the lockout is insufficient flow of water in the CH circuit causing a safety sensor to trigger. You can check this by having one radiator where the manual valves at either end are fully open. Or remove some of the smart TRVs.

  • all smart except the towel rail which is standard trv set to 2/3 ,

    but all was working with the Lghtwave rf heating control and smart trv's for a few yrs previously

  • will check the other end valves though

  • Assuming it is an issue with flow through the radiator circuit. Perhaps the Lightwave TRVs were passing a small amount of water when closed. Or perhaps the Lightwave controller was opening a TRV before starting the boiler. Whereas Tado starts the boiler before opening a TRV.

  • so possibly a software issue

  • davidlyall
    davidlyall ✭✭✭

    @GrilledCheese2, in my Tado experience, the TRV opens then the extension kit relay clicks to start the boiler

    I do agree that it's likely a flow issue which should be easy to check with at least one radiator left fully open

  • as the towel rail is a standard valve ,and not controlled by the tado ,

    would this scene be covered ?

    have been given a load more checklists to do by support just haven't had the opportunity ,

    saved mew a fortune on heating through not working though !

  • Have you tried fully opening the towel rail trv yet? If it’s not a smart trv then it’s effectively invisible to Tado.
  • Pukington
    edited June 10

    Just pop off a couple of TRV's so there's flow through the system then test it. I had an issue when I first fitted Tado TRVs that I didn't have enough flow and the boiler threw an error. In the end I left the towel rad and a corridor rad with no trvs and that solved my issue. I just rebalanced the system using lockshields on these two rads.