Home heating automation

No, it works away as normal. Tado HW is timer only, the cylinder stat will interrupt a timer call when set temperature is reached.

If you have a two independent zone system, with seperate zone valves to switch the flow for HW and CH, then its a direct replacement. If there's an existing wired thermostat (optional connections shown on the wiring box diagram you posted), this is simply turned up, or removed and linked, either in the wall or across the wiring box CH Thermostat terminals.

Even if your system was a gravity system the Tado can be configured to give "1½ zone", with HW only or CH with HW.

The only incompatibility with EPH is if your HW Thermostat is an EPH wireless one, but the R27 is just a simple two zone wired controller. I assumed your cylinder stat is wired, if it were wireless it would have to have it's own receiver independent of the R27, but I'm not familiar with an EPH version of this, just the EPH Ember wireless controller which directly recives EPH wireless cylinder stat signals. This controller is not completely compatible with Tado, or a all other controller receivers, and would require either the installation of a wired cylinder stat, or leave the Ember in situ to provide HW stat live supply while moving CH over to the Tado. Thems the scenarios in Ember replacements where an Ember wirelesscylinder stat was fitted

If you mentioned stove heat source in the configuration questionnaire it might have thrown them. Work away and enjoy, safety first with mains wires.

You're welcome. Once your wiring is tidy and traceable it's not too difficult.

Nice one.

Iirc, in the event of an Internet outage, schedules continue on the last temperarure setting per device, but you continue to have manual control at the device. The V3 bridge is also visible within your LAN, so can be addressed locally by home automation apps, such as homekit, allowing some access to local automation. If Internet is down because of a power cut, the offline access is moot. I'm a V2 owner, 7 years exactly this week. with possibly one later V3 TRV, so at most I can maintain a TRV schedule, assuming it continues to call the boiler via the V2 wall stat relay.

I've had only one prolonged Internet outage in that time, well over a week at Xmas when the I assume the eircom techs workers slipped into the pub beside the cabinet, without properly putting everything back, my linechalf plugged in. It was gone 5.00 on Xmas eve when I noticed, admitted days before anyone came back. My solution was a simple WiFi extender plug that had an ethernet port, paired to my phone hotspot.

You're missing a wire, it may have dropped inside the plaster board. The wire to send switched live to the boiler goes to the CH NO, normally open, which connects to the live you jumped to CH Com when the CH comes on. This wire would have been connected to V on the Hub.

Its possible the Hub was configured in two wire mode, like a mechanical thermostat, with only live in and a switched live out from the V terminal. This was designed to allow the hub replace two wire mechanical thermostats with only live in and switched live out.The hub had a rechargeable battery to operate its electronics, and in the absence of a neutral, it used the load on the v wire, a motorised valve or the boiler switched live in, to provide a trickle path to neutral to keep the battery charged. If this was the case, then there is no direct neutral from the main switch above, and the wire you've connected to the neutral is actually the SL to the boiler. If so,it doesn't help thar it's using blue neutral cable. Can you remember if there was only a live wire into the L terminal, and the other wire was connected to V, with no wire to N?

Hub wiring with permanent neutral below.

Hub wired as two wire, with virtual Neutral.

Whatever wire was wired to V carried the live to the boiler. As you previously had an Apt timer prior to the hub, this would have had a permanent Live and Neutral supply, a switched live (SL) to the boiler and an possibly an earth wire. When the hub was installed, there would be no reason to wire the hub in two wire mode, but perhaps the installers pushing these things in everywhere were only trained to do this, and I note the battery warning sticker on the main power supply, which implies it was working from parasitic charged battery, which implies that the hub was in 2 wire mode. The Tado can supply the switched live to the boiler, and it needs a live and neutral to power it. First step would be to open that labelled switch and see what is being supplied to the hub/tado. Is the blue neutral wire actually the SL to the boiler? Perhaps they used the green/yellow. I've seen this in this thread before.

Unfortunately there's a cabinet built in top of the switch, so it's not going to be easy to inspect inside. Its a pity you didn't note the wire connections to the hub. Where was the green/yellow connected? There is no earthing point in the hub, as it has no metal casing. I'm putting my money on the following. Live and Neutral were connected to the hub L and N, and the green/yellow was used to send SL to the boiler. If otoh the N wire is actually the SL, then if you unplug both the boiler and pump from inside the boiler casing, and the Tado stops working, this will tell if the Tado is finding a neutral line via the pump/boiler windings and not by a direct connection to the mains neutral point in the obscured switch. These are the two possibilities, and you would properly need to use a meter and phase testers to see what goes where. If you find this too challenging, you will need an electrician to discover exactly which wire was used to direct the SL to the boiler, but using blue or green/yellow is reckless and an accident waiting to happen.

Bloody 'ell. Who wired the APT originally? Using green/yellow to carry live is criminal. Sticking a bit of black tape on it is ironic, suitable colour for death

It'll work if you move that taped wire to CH NO. That's possibly the supply to those sockets, but ideally the boiler should be powered from a normal permanent powered socket, and the SL from Apt/Hub/Tado should go to a relay terminal in the boiler to fire it. This way, the device is not supplying the large current required to kickoff and maintain the boiler, just a lower current to switch the mains in the boiler. Is this an older boiler? Some old simpler boiler house models were often just direct powered on and off. The relays in the digital type devices might not be able to cope with the surge, the higher amperage might fuse the contacts. Apt timers were designed for this with heavy duty contacts. If you have the boiler model name and number, I can check and see if it has permanent live and switched live control it would have to be ancient not to. That said, sometimes modern boilers are wired incorrectly with just a switched live turning the whole thing on and off like a light bulb, with no standby power when it's not firing.

That is the most basic boiler setup possible, straight mains into the Riello burner. Its a low power consumer, only 115w when running, so the current capacity of the Tado relay is not an issue. The problem usually lies with the surge from this and the circulation pump at startup. These motors can pull quite a kick initially, and the condenser on the motor may be well below spec, which can increase the surge, but able to 'kick' the motor still. Its this kick of current that can cause arcing over the small relay contacts fitted in the controllers. I'd be fairly certain that's what took out the relay in your Hub. There have been a couple of posts over the years from lads with stuck contacts on the Tado wall stat, or the extension kit, and direct boiler power is the culprit.

My advice is to connect the V wire (black taped yellow/green) to the CH NO terminals and get the system running. You should then consider getting either a mains to mains relay of at least 15A to shift the inductive load from the Tado, or perhaps upgrade your boiler to a condenser model with modern always powered controller. That old grant is shoving 20% or more of your heat out the flue. It doesn't have a controller

I had a similar setup 23 years ago when I moved in to my present abode, the boiler was a huge cast German thing with an RBD burner, already maybe 15 years old, only 68% efficienc. The timer was a grasslin segment clock like an APT, it soon after failed from burned contacts, and I replaced it with similar. It also burned the contacts of the boiler stat, the box you see inside the cabinet, I managed to clean and repair those. When I decided to modernise the heating in about 2017, I new I'd need to lose the old boiler before fitting electronic thermostats with delicate mains relays.