Drayton thermostat to TADO V3+ smart wired thermostat

[sergipot]

Hi all,

At the moment we've got a Drayton wired Thermostat to a TADO V3+ SMART WIRED HEATING THERMOSTAT.
The Drayton is a 3 wire installation and I could see in the tutorials that the Tado thermostat has only two cables.
How would be the way to change this? How would it be possible to install the new smart thermostat if it only requires 2 cables?
Is there any thermostat that is 3 wire so the set up could be the easiest?

Any experience moving from a 3 wired installation to a smart thermostat, will be very appreciated.

 

[stem]

Yes the Tado is battery operated so no neutral is required. Isolate it safely out of the way, then, the Red and Yellow wires go to COM and NO

 

[sergipot]

Yes the Tado is battery operated so no neutral is required. Isolate it safely out of the way, then, the Red and Yellow wires go to COM and NO

Thanks for your reply Stem!
I didn't know the Tado thermostat was battery powered. So I would have to keep buying batteries?
Do you think the Nest thermostat would be easy to install? And do you know if the 3-wire is compatible?

 

[stem]

Yes, all smart thermostats with just two wires will be battery powered, but the batteries will last a long time possibly a few years and the thermostat will tell you when they require changing.

As your existing thermostat has 3 wires, you have the option of fitting a 2 or 3 wire thermostat in its place.

Nest is more difficult to install as it will have a 'receiver' that the three wires from the thermostat are connected to like this:

And a separate thermostat that needs to be wired using 2 wires to the receiver to get 12v operating power, or it can be powered by a separate plug-in USB power supply.

As your existing thermostat doesn't have any time control, I assume that there is a separate timeswitch / programmer somewhere. That would need either to be removed and the wiring modified at the timeswitch, or left in situ and set such that the heating is permanently 'on' and then the new smart thermostat would control both time and temperature functions.

If you have a heating system with a separate hot water cylinder [not a combi boiler] then the Nest receiver can control that too, but the wiring becomes more complicated.

 

[sergipot]

Yes, all smart thermostats with just two wires will be battery powered, but the batteries will last a long time possibly a few years and the thermostat will tell you when they require changing.

As your existing thermostat has 3 wires, you have the option of fitting a 2 or 3 wire thermostat in its place.

Nest is more difficult to install as it will have a 'receiver' that the three wires from the thermostat are connected to like this:

View attachment 331541

And a separate thermostat that needs to be wired using 2 wires to the receiver to get 12v operating power, or it can be powered by a separate plug-in USB power supply.

View attachment 331542

As your existing thermostat doesn't have any time control, I assume that there is a separate timeswitch / programmer somewhere. That would need either to be removed and the wiring modified at the timeswitch, or left in situ and set such that the heating is permanently 'on' and then the new smart thermostat would control both time and temperature functions.

If you have a heating system with a separate hot water cylinder [not a combi boiler] then the Nest receiver can control that too, but the wiring becomes more complicated.

This is making me not want to change anything! If the battery lasts that long, I wouldn't mind then having the Tado thermostat.
So my actual set up is a combi Worcester boiler that manages heating and hot water.
I have the thermostat to manage the temperature when the heating goes on but that's the only thing it manages.
The rest is managed through the boiler controls:

 

[stem]

So it's a combi then, therefore the hot water control remains as it is. The CH would need to be set to be permanently 'on' at the boiler and then a smart stat of either the 2 or 3 wire variant would use the existing wires that go to the existing thermostat. The new thermostat would then provide sole control of the heating temperature and time.

BTW, your boiler pressure looks low.....err very low....

 

[sergipot]

So it's a combi then, therefore the hot water control remains as it is. The CH would need to be set to be permanently 'on' at the boiler and then a smart stat of either the 2 or 3 wire variant would use the existing wires that go to the existing thermostat. The new thermostat would then provide sole control of the heating temperature and time.

BTW, your boiler pressure looks low.....err very low....

Ha! If that was my boiler I think I'd be having some big issues

Would it use more energy because of being on in the boiler all the time?
Is it really worth it to move from my actual thermostat to the smart Tado thermostat?
Would you recommend any other brand?

 

[ericmark]

With a modulating boiler, the thermostat is really only there to stop boiler cycling as the summer approaches. Unless using a modulating or a linked wall thermostat likely the old one will do a better job.

Each room should be controlled by a TRV (thermostat radiator valve) and idea is it is anaguloge control so it slowly increases or decreases the radiator temperature, and the boiler sences temperature of return water and alters output to suit.
Clearly it can't stop/start boiler so still need wall thermostat, but it can first modulate then cycle.

However I at least do not want 24/7 heating, and would prefer to turn up/down target temperature rather than on/off, so a programmable thermostat makes more sence.

So I had 10 programmable thermostats, one wall mounted and 9 TRV's.

Better if linked, mine are not, but now looking at cost. A wall thermostat Hive, Drayton Wiser, Honeywell Evohome etc will cost £150+ and the TRV heads around £56 each. But a TRV which does not link, is half the price, 2019 when I got my eQ-3 they were £15 each, and think my Kasa was around £24.

So you have to decide how far to go. The more you pay easier to set up, but you can set up simply using the lock shield valve.

I have tried to set up three homes, my last home easy, mothers house too some more doing, still trying to set up this house, after mothers house I was sure I had all the answers, then got this house.

But thermostats with degrees C marked on them are far easier to set up to *123456 so electronic heads are likely the best option.

 

[stem]

Would it use more energy because of being on in the boiler all the time?

No, because the boiler wouldn't actually be 'on' if it was 'off' at the new stat. Electrically speaking, nothing changes from what you have now.

At the moment the boiler timeswitch and the thermostat both have to be on for the heating to work. With a smart stat it performs both functions [time and temp] so even though the boiler timeswitch was on, the boiler wouldn't fire up the heating until the stat says it can.

Is it really worth it to move from my actual thermostat to the smart Tado thermostat?
Would you recommend any other brand?

That my friend is all down to your personal preference.

 

[Deleted member 267285]

As @stem has said, personal preference and plenty of thermostats on the market. What are you trying to achieve that your existing thermostat lacks?

 

[sergipot]

As @stem has said, personal preference and plenty of thermostats on the market. What are you trying to achieve that your existing thermostat lacks?

To be honest I wanted to be able to control my heating better.
At the moment I can only set up 3 different times for the heating to come on during the day. And of course if possible if it can help the heating to be more efficient and economic.
Do you think I can achieve these results by installing a smart thermostat?

 

[Deleted member 267285]

It can be possible for possibly being slightly more efficient with tpi technology, not sure about the more than 3 times periods. Have a look at Esi, EPH and the latest Drayton Digistat

 

[ericmark]

How to use less energy comes down to reduce hysteresis, or any other over heating and only heat room when required.

The latter depends on recovery time, faster one can reheat a room without over shooting the less time it needs to be heated for.

So for my house, 4 rooms down stairs in the flat can be turned off, or at least set to defrost temp. for that one pump turned off an motorised valve.

Main house bathroom no control, shower room simple TRV, rest programmable TRV heads.

The problem is to ensure when a room needs heat, the boiler is running, due to non modulating boiler I need to drop main thermostat in hall half a degree half hour before a change and up again at change time to ensure boiler runs.

However your boiler modulates, so as long as not off, a TRV opening will auto increase boiler output. Using TRV's means less hysteresis so big question is what does the wall thermostat do?

If each room is controlled by a programmable TRV, then all the wall thermostat does is turn off the boiler in summer.

So simple is the eQ-3 or Terrier i30 set to back ground heat, and on coming to use a room you press button on it to swap from eco to comfort, and vice versa.

From there you can progress to linked TRV to wall thermostat, but then there is a jump in price. So around £25 each TRV non linked £55 each linked, so this house 9 TRV heads and wall thermostat linked around £800, that will buy a lot of oil now 72, so is it worth it?

 

[Mister Banks]

A smart try that doesn’t control a boiler is basically no different to a manual trv so unless you want app control I think a smart trv is not of much use.

 

[ericmark]

Boilers (modulating type espicially) can be controlled either electrically or using return water temperature. Or of course both.

So there can be cleaver algarithums drive controls, but keeping it simple.

1) TRV closes.
2) By pass valve opens
3) hot water returned to boiler so boiler closes down

In real terms more gradual, as the TRV closes first more water forced through those still open, then by pass gradually opens, and the boiler gradually reduces output until at minimum, then it starts a mark/space ratio to further reduce output, and anti cycle software increases off time, however it can never turn fully off.

So we need a wall thermostat so on warm days it can turn fully off, which is placed in a down stairs room normally kept cool, with no alternative heating or outside doors.

This is rarely possible so some near enough engineering or the TRV's are linked to the wall thermostat.

Hhowever the point is primary control is the TRV, and to better control the TRV is normally key item to the improvement.

OK always exceptions, open plan homes, fan assisted radiators hot air heating, but not really looking at the special case.