Home heating automation

Hey all (but mostly @deezell haha).

Looking to help someone replace the below:

3 heating zones and 1 hot water zone.

Wired thermostat per zone with a central programmer (EPH) that has control over each zone plus the hot water.

Can this be replaced by three wired Tado stats? And do they need one more stat for hot water? They want to add the TRVs as well and the quote they got for this part of the work was all Hive gear (didn't work out how that'd be put in but I'd imagine just wire the Hive receivers at the zone valves in the boiler "room" and put the wireless stats in where the wired are, hiding the old wires and one of the stats would control hot water as well) and fairly pricey.

You're on the money.

Option 1. Tado wireless starter kit to get extension kit with hw control, plus one wireless stat, and two additional wired stat.

2. Tado wired starter kit plus two extra wired stats. Leave eph controller in place to manage HW timing. turn eph CH zones' timing to always on, Tado stats take over temperatures and timing of the three CH zones.

3. Three hive stats and receivers, one with HW timer and Internet hub. Remove eph controller and wire these to the output wires. The CH wires go to the eph wall stats and back to the valves, so either, leave them there turned up full, or, remove and link the internal com and NO wire, push back into the wall and mount the Hives over these.

Tado (and Hive) don't have a stat for HW temperature, just timing control switched live, SL, from the receiver to the HW valve. This may go via a mechanical stat on the cylinder, which might already be in place.

Hive kit in Screwfix is €169 for CH/HW/Hub kit, €113 each for two CH only kit without Hub. Total €395.

Tado kit in Screwfix is €120 for wireless CH/HW/starter kit, in Black, (€236 in white). €104 each for extra wired stats in Black. Total, €328, an absolute steal. No white wired extra stats in stock in Screwfix, but these are €137 from ie.shop.tado.com (frustratingly priced in £). So in white, total is €510.

TRVs prices vary, with deals, etc Tado now do a basic or EcoTRV for €69, original model is €89. Screwfix more expensive for these. Hive TRV only €56 in Screwfix, but they're not the Mae West if you read reviews. You might get Tado premium one's for a lot less than €89 if you watch out for deals. Currys have a 4 pack for €70 each, and the wireless stater kit in white for €220. Plenty to chew on there, and you can consider Drayton wiser if you wish, a Kit 1 and Kit 3 will do the job there.

The plumber should be au fait with S plan. First is a generic S plan for two zones, in the case of Nest, the CH stat is not wired in, as its wireless to the Heatlink receiver, so the device shown as programmer/timer is the Heatlink in your case, though terminal nos don't match.

The next is the actual wiring for S Plan using the Nest. Note also the two wires on T1 and T2 also linking the nest heatlink to the Nest wall stat. These are optional low voltage power and comm wires. The stat can communicate wirelessly to the heatlink receiver normally, and get its power from a mains adaptor. The two wire power option can be implemented if you are removing an existing mechanical wall stat, and there are two wires to the terminals in the stat. Provided these are disconnected COMPLETELY from any mains at both ends, (the stat and the boiler or zone valve), they can be used to provide a ready wire pair to power and wired comms from the Nest to the heatlink, but its crucial that any mains previously connected via these wires is removed,otherwise you'll fry the nest wall stat.

If you intend upgrading to S plan from your existing single zone valve, then this covers it. If you were to just leave the one valve system, the wiring would be a little different, and would also depend on your existing zone valve having and Internal relay, which it may have unused. Let your plumber put in a CH valve and do the S plan, he should be able to, though he might want a sparks involved.

You can only have one wireless stat. Two have to be wired. TRVs are paired to whatever stat, wired or wireless, that opens the zone valve of the location they are in. If you have an upstairs wired tado stat, the any trvs on upstairs rads will call the boiler and open the upstairs zone valve by closing the relay in the wired upstairs stat. This will occur even if the stat is Off due to being at its local target temperature. Ideally the rad local to the stat, (say on the landing), will have a TRV, as will stay closed though the stat has called the zone and boiler for a bedroom stat. The landing TRV can even use the Stat sensor for more accurate temperature measurement. As always, open rads in the zone without smart TRVs or with mechanical TRVs will heat when any smart TRV in the zone calls for heat. These are usually minor rads like bathroom, towel rail, en suite.

(I assume this is regarding your own setup, not your friends). It could in a sense, a wireless sensor is used to give better temperature readings for a smart TRV. The TRV is configured to use the wireless stat sensor instead of its own. This in turn is paired to a relay to open the zone/fire the boiler. This relay is either a wireless ext kit or a wired stat. If you pair it to the wireless stat/extension kit downstairs, it will open the downstairs zone, so you will just have a single zone.

If you have no wiring for a wired upstairs stat, but intend using smart TRVs upstairs, there is no need for this wired stat to actually be located upstairs. It can be located by the upstairs zone valve, with the TRVs addressing it as a relay only. In that sense a wired stat can be the equivalent of a wireless stat receiver. If I'm not mistaken, the wired stat's own sensor can be disabled, or just set to a low temperature schedule, so it only triggers for paired TRV events.

Again, if you place a sensor stat upstairs, it can be the trigger for the wired one connected to the upstairs zone valve. I'm unsure if this new sensor stat can stand alone like this, without being the temperature measuring device for a TRV or TRVs, but I don't see any reason why not. It would fill the gap in Tados armoury, in that they could not have multiple wireless stats to receivers. I've not come across any clear information in this regard on the Tado forum, though I have seen queries from users trying to achieve a similar end, e.g, an all TRV installation using the ext kit as the relay, without the paired wireless stat. I think Tado are evolving their architecture from their original product to something similar to Hive and Drayton, but as I said, there are more questions than answers, as Johnny Nash used to sing in the 70's.

As per usual - brilliant stuff!

Yeah, Tado's obvious "gap" is not just supporting multiple wireless devices on one account, the "sensor" stat places in the location that the wired stat is connected to (in terms of zone valves) is a workaround but means the user needs to buy two devices versus one.

The obvious problem is the intermediary between old school fully wired and these smart wireless systems - namely radio band style wireless stats. Hive's design and ability to have multiple truly wireless stats makes this easier.

The Hive mini also gives Hive the price advantage. Not sure of the drawbacks of it so need to research that.

For heating and hot water you do need the wireless tado starter kit as the normal wired tado thermostats don't support hot water management.

For swapping from heatlink to Tado most threads suggest going for wireless as well, even when with a combi boiler:

https://community.tado.com/en-gb/discussion/13371/moving-from-nest-to-tado-help-needed

For more info wait for deezell ha.

Definitely wait for deezell, should have the info. 🤣

There's definitely been previous users he's assisted with your setup (as it's hugely common in Ireland).

Think you @VinLieger might need to confirm if you use the bath / sink switch - i.e. do you have an electric shower and so this switch just stays on sink, or do you flip it etc.

@deezell

Yeah.

Definitely seems like it's not in Tado's wheelhouse, and they don't want to make it in their wheelhouse but an experienced user has made suggestions to them.

If you want to Geek out and see other options suggested to make an immersion smart:

https://community.tado.com/en-gb/discussion/8435/hot-water-monitoring-tado-hot-water-tank-thermostat

Oh, was that that the Bat(h)phone just rang? Let me get into my costume first..

The HW control you're switching is the immersion heater, off the electric. When you operate your central heating does that also heat your cylinder of water? Were you able to set HW times on your nest Setup? Regardless of this, if you are currently using a Nest 3rd Thermostat, even if only for CH, the stat itself is not wired directly to fire the boiler, or open a zone valve if present. This is done with the Nest Heatlink box wired beside the boiler or zone valve, and this connects wirelessly to the Nest stat*. You may only have the Nest E stat, which has no HW control and a simpler battery powered heatlink receiver. Because of this, the Tado wired stat will not have a direct wired pair to connect to when you swap out the Nest for the Tado. The easiest swap is to get the Tado wireless. Then the Tado stat can be located anywhere, fixed or on a stand, and the Tado receiver, the extension kit, will replace your Nest heatlink receiver. Can you confirm which nest you have, and if you can use it or the app to set HW timing.

* There may be existing wiring from a previous mechanical stat in the wall if your Nest replaced such a stat. Furthermore, Nest gen 3 can re-utilise this wiring (if fully isolated) to provide a low voltage power and data connection between Nest stat and heatlink. Such connections have to done correctly to avoid live mains from the previous mechanical stat connection destroying the heatlink and Nest. Have a look at the last diagram on this post a few days back https://www.boards.ie/discussion/comment/119746888/#Comment_119746888

Now, where TF did I leave my Cape?

So you probably have a single zone system. Prior to the Nest install it may have been possible to heat HW without the CH if the old thermostat (if you had one) was only connected to a CH pump or valve. If the boiler is in a shed, I'm guessing no gravity feed to the cylinder. CH and HW heat together, so you use the immersion in the summer for HW.

If you're getting solar, Eddie, etc, consider the installation of some zone valves to isolate CH from HW, though it might not be worth it if you can now heat HW from your panels during the summer, that may be all you need. (heating HW only with a 35KW oil boiler, even a condenser one, is not as efficient as people think, as return flow temperatures are generally high because no CH is on. Its probably still cheaper the electric HW heating, but with free solar, its the way to go.)

Nope, it's an amazing deal compared to tado's own price.

Unfortunately they don't seem to stock add on units in black and are sold out of add on wired units but that doesn't impact you.

Sorted it!!!!!!! Turned off the bacteria prevention and now everything is working fine !! Bloody hell 2 hrs pulling hair out!!! Any every come across this?

I’ll turn that on in a few days and see how it goes, is it a necessary feature that needs to be turned on? There is a filter at the boiler now which wasn’t there before. On a side note we had to use a eph relay to connect 2nd thermostat, there was wiring for a 2nd thermostat but it was just left in the stud and we couldn’t find the other end.

I’ll use nest thermostat With the stand as didn’t connect it to the original thermostat wires in the bedroom.

@deezell that’s exactly the filter that the plumber put in. Good to know this.

I wasn’t there when they were doing it ,I only arrived as they were finishing. For what I could gather, The reason they put this relay in was because they couldn’t find where the 2nd thermostat wire went to!! I’ve never had 2nd state and didn’t realise we even had the wire there. So they put in the relay so I could boost hot water I think.

my set up know is best can now boost hot water and I can switch eating on and off along with all the scheduling and the rest of the bells and whistles. I might look at that further down the line when I replenish some funds.

what’s the benefit of fitting this to a nest e as appeased to just leaving it on the eph Relay ?