Tado only delivering CH when HW is heating up - how to troubleshoot?
I've just swapped out my old Honeywell ST9400C for the Tado Starter Kit & 9 x TRVs - Installed and followed the Y-plan wiring guide. (Had this checked over by a 2nd pair eyes too). So far so good.
The system will call for HW and heat up the water in the tank to 65C as requested and at the same time send heat to the rads but once the HW tank is done, it all stops - CH too.
I have the tdo wireless thermostat connected (I've bridged and removed the old dumb one with the twisty dial) and Tado smart TRVs on each of the 9 rads (all connected, no errors) but I can't get the wireless thermostat or the TRVs to trigger heat to the CH.
I've paired, unpaired, re-paired everything loads of times - I've traced the wiring and had it checked - and still nothing.
I'm basically stuck - the software says 'all good' but it's not - it's blooming freezing!!
I'm IT/computer technical so no issues on that side but not sure what I can do and where to start - help appreciated!
Best Answer
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So I didn't want to be THAT person that leaves a thread dangling and unanswered so I'm just closing up here with the successful resolution so that others can benefit: it turns out that the Honeywell V4073A1039/U 22 mm Mid Position Valve's Actuator Head (not body) was malfunctioning - it seems that the gearing mechanism inside it refused to mesh with the arm and it was slipping, never reaching the CH valve position and thus never calling for heat from the boiler.
I replaced the actuator head in 5 mins, cost £15 for a 2nd hand unit from ebay (barely used) and life is now much warmer. Way, way quicker and cheaper than using the local plumbers who can barely be bothered to answer the phone.
Tado support wasn't particularly useful I have to say - was slow and didn't follow up - but then they'd argue they have this forum (precisely because it saves them money and maximizes profits, but I digress).
Since then the Tado units have performed as expected. nice.
Thanks everyone else for your suggestions and assistance along the way - kind people :)
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Answers
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I had the same issue when I first set up my system. You need to contact tado and they will change the configuration for you.
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Thank you - but what does that mean 'change the configuration' - can you please elaborate?
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I've wired back in the old (working) Honeywell t40 thermostat/roomstat and the Tado controller/programmer is STILL not calling for heat, unless I demand the hot water tank is heated up (by manually upping the temperature on the tanks thermostat (honeywell).
Feels like I need something else to check at this point - the tado app doesn't give me much help and support aren't replying. Any ideas anyone?
thanks.
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Have you checked the configuration is set for y plan? Google ‘Tado wireless receiver manual’ and it will tell you how to configure it.0
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@zippydoda tado connected to my system remotely and updated the settings/configuration. It's not worth going round in circles. Contact tado and they will assist with this.
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@royi appreciate the suggestion, I've asked support but they are slow AF, and now 'back Monday' apparently....
What exactly do they do to the software remotely? And why isn't it standard out-of-the-box working - my setup isn't remotely unusual. Any ideas?
I hope they can fix it but honestly for £600 on kit you'd expect a number to call or someone to make it a priority :/
Fingers crossed .... I'll report back either way.
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It seems like support is getting worse, compared to last year. I accidently configured my heating as gravity heating? (heating and hot water comes on at the the same time). Contacted tado and they changed a settings on their side.
I'm sure it is fixable and their support will be in touch.
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I've now got the Tado Controller calling for heat (the light is ON) and yet the boiler never fires up. HW test however does get the boiler firing up - I have to push the 3-way valve into MANUAL to get hot water circulating around the house as the valve won't move to CH-only mode. Is this a known issue?
Help appreciated.
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I think you’ve found your problem - your three way valve is sticking. Was it working before you installed the tado system?1
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Yes, it was. And even if it's sticking it's still a 'valid' option to have it in manual - yet the signal to start the boiler/pump just isn't making the boiler pump start up which I presume it should?
Is there a scenario - unlikely I know - where I remove the electrical coupling to the 3 way valve entirely and just have a manual/mid-position selected and run like this? My question is: what is making the boiler not fire up? does there 'have to be' a 3 way value electrically coupled to the boiler for the 'start up' signal to be activated?
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I’m not a professional plumber but i would think removing the valve would result in the heating being very slow because it’s also filling the hot water cylinder and you being unable to use one without the other.
I haven’t seen your wiring but I would say the issues could come down to
- a relay in the tado wireless receiver itself sticking (can sometimes be solved by tapping it with something)
- the wireless receiver being incorrectly configured
- incorrect wiring to the valve
- a problem with the valve itself1 -
The contacts in a three-way valve (mid-position, HW priority, valve) should call the boiler for heat. In a previous life ... a faulty valve and/or mis-wired timer/controller unit (Tado or non-Tado) can show strange symptoms.
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Yes, that's a key piece of information that many folk don't realise.
When a wired thermostat (Tado or otherwise) demands heat it's actually just telling the motorised valve to open. Once the valve has moved to it's open position, a switch inside the valve closes to tell the pump and boiler to run. If the valve fails to operate then the pump/boiler won't start. There is no direct link between Tado and the boiler in a relay-based S- or Y-plan system
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Good to know! Be useful if tado put that into the guides for troubleshooting etc. as it might make it easier to debug errors. I'm amazing at just how crude the old CH system are/were - seems even odder that the signalling systems need to run on 240v also - can't they get away with 12v? anyways, issue sorted.
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Spot on David. This is like explaining the central heating boiler S-plan valve and wiring to SMWBO’s brother-in-law in 1992. I’ve lost a lot of hair and patience since then.
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@zippydoda pleased to hear the problem is fixed.
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@wateroakley I imagine it's a bit like trying to tell certain members of the household that turning the thermostat up higher doesn't heat a room any faster 🙄😁1
