Tado V3+ thermastat issues

Hi ​@TayUK 

Did you manage to diagnose the problem?

Hi, thanks for the response. 

It's a standard boiler as far as I am aware, there is an immersion heater tank (I think), I say this as she has 2 thermal panels on the roof and a mass of pipes that frankly have no idea what they do or where they go. 

The gauge on the front of the boiler does not work, it was serviced several weeks ago, the pressure is shown on one of the digital menu’s, currently (or at least 3-4 days ago when I was there) it was showing 1.1-1.3BAR I think. 

I understand that this is a known issue with this boiler model. The plumber mentioned during the service this is a known issue and confirmed the system was pressurised as expected. 

My mum lives in a bungalow and everything is on the ground floor.  The boiler sounds perfect when it's running, as mentioned putting the Tado stuff through its tests (heater button on the receiver) the boiler kicks in after a short delay and the radiators heat up, but this is a temporary thing as the test mode only stays on for a few mins..   

The wifi signal to the back of the house (Where the receiver is) isnt terrific but the receiver seems to respond when manually triggered, there has been times when this has not worked though.  

This morning the heating wasnt working again when I check at 07:45ish, it should have come on as per the schedule below,  you can see even after I managed to get it going (pressing Temp up/down/hot water button on/off - boost rooms etc on the app) briefly,  it changed its mind and stopped again a couple of times, its currently turning on and off as expected at around 23 degs’C 

I have been told that it could be possible to get an offline schedule configured that could mitigate the issues seeing but its a work around as opposed to a fix. 

Currently, its 50/50 as to whether the boiler comes on as per the schedule.

I’m back home down south and no further along the diagnosis trail.  Its made significantly harder not actually being there. 

I presume this is going to be a Tado support issue despite the fact there appears to be some sort of integration with the OVO Energy website?. 

tks

AFAIK, yes. Tado Support would be the best place to ask for help - OVO isn’t responsible for providing support for Tado devices.

To me that does not sound right.

What kind of service does not replace faulty/broken parts?

Is your mum being ripped off by “The plumber”?

Good question, I suspect it might have been particularly expensive part perhaps..

I been thinking a bit more.

Often it isn’t the guage itself that is faulty,.
If the boilers internal expansion vessel has failed (which they can do) then when the boiler circulation pump is running the system pressure rises and instead of going into the expansion vessel like it should do a bit of the water in the system gets exhausted through the pressure relief valve, resulting in less water in the system.
That then shows up on the gauge as low pressure when the pump is not running.

To be fair it is on the water system not the gas, so it’s not so much of a safety issue.
If the pressure drops too low then the boiler won’t let gas in and won’t fire up at all.

You can just keep topping up via the filling loop, many people in such a situation do, but the real solution is to replace the faulty expansion vessel and that’s a much bigger, more costly, job than just changing a gauge.

I still think that next time you visit I would be checking the service contract, (if there is a regular service contract), or if it was a one-off service just what was supposed to be covered for what your mum paid.

Other than that would be a choice of keep topping the water up as needed, or pay to have the expansion vessel replaced (or even get the boiler replaced).

Hi ​@TayUK 
As you are well aware diagnosing problems at a distance can be a real pain.

The standard Tado V3+ comes in three parts, the internet bridge (which is connected to the wi-fi hub), the controller (which is wired to the boiler) and the thermostat.

Is the Tado at fault?

A few things make me question that the Tado is faulty or not communicating as it should. The thermostat seems capable of transmitting back the current temperature, and the controller the state of the hot water, and also the control signal to the boiler (1, 2 or 3 bars relating to the colour of the shading). This suggests the three components are all talking to each other and also over the internet.
Also what changed on the 22nd after, several months, to cause the issue?

Looking at the various possibilities.

Low water pressure: If the pressure is marginal then increasing the temperature slightly, like heating the water cylinder, can increase the pressure in the system and cause it it start up. Your graphs from the 22nd and 28th both show the system springing back into life after a hot water cycle. By the way does the hot water cylinder heat up? If it is this again hints that it is not a Tado comms issue. Nukecad suggested that one possible cause is the over-pressure relief valve operating at too low a pressure. I think the EcoBlue has a separate expansion vessel and pressure relief (so cheaper to fix if this is a problem). It is a shame the gauge isn't working as this would make it much easier to check.

Faulty/sticking pump: It is possible that the circulating pump doesn't want to start. Our neighbour had this issue and would give it a deft tap with a spanner to persuade it to start (NOT recommended). This tends to show itself when the system has been off for a few hours. Once running it would run happily for the rest of the day until the next morning.

Faulty/Sticking zone valve: If the system is "Y" plan (it has a three port mid-position valve) then it may be that the valve is sticking. If the valve motor/actuator failed then generally you get hot water but no heating. If the return spring (within the valve) has failed then the valve can get stuck in the heating only state. I have seen washing draped over the valve (it does get nice and hot) which can cause the valve to jam.

Boiler bypass operating: Some systems have a bypass valve which ensures a minimum flow to the boiler. Basically when the flow through the radiators falls too low, the pressure from the pump rises and the relief valve operates diverting flow back to the boiler. This is common in systems with pump over-run where it is neccessary to maintain flow through the boiler when the valves close off. If this valve is sticking then it can be sending most of the water flow straight back to the boiler rather than through the radiators.

And there are always loose electrical connections on the Tado, boiler or valves.

In some respects fault finding with a Tado can be easier, as you can turn things on and off whilst watching the valves operate and feeling which pipes warm up.

Just food for thought really
 

Hi ​@TayUK, as ​@BeePee intimates, one of the Tadö parts, the sensor or the “room stat” bit, you may remember has three of the common small household batteries used in so many handsets etc. (AAA alkaline batteries) located in their own compartment.  To access them, the sensor is just gently disengaged (from the bottom edge, and then easing upwards) from its mounting bracket, no screwdrivers or other tools or indeed particularly strong or adept fingers required.  I’m wondering whether these batteries have maybe started failing a bit and whether that could account for months of good reliable boiler control fading into the sudden randomness in performance your Mother’s experiencing? I haven’t had my Tadö long enough to know whether there’s any self diagnosis that reports low battery reserve, or even whether that would account for the particular symptoms in this case?

Bit difficult, though, I appreciate, for you to check with new batteries from 150 miles away! Maybe a friendly neighbour would be prepared to be talked through things on the ‘phone?

Hope you get things sorted soon, all the best to you and your Mum for the New Year…