Replace existing thermostat with WiFi version

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I'm planning on replacing my existing danfoss tp4/5000 with one of the numerous WiFi thermostats available from China. There are a few different designs but the contacts are more or less the same.

Just want to clarify the following will work. Attached is a picture of my current thermostat with is battery operated so no live terminals coming through. As well as the wiring diagram of the new one "GC" drawing.

Can I replace this existing > new with:

2- 1
3 - 2

And then power it up using live / neutral?
 

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Yes, but where are you getting a permanent live and permanent neutral from? You mentioned no live terminals coming through but that brown wire could be 240vac live.
 
As above- just because there's a black wire there don't go thinking it's a neutral- it won't be, you'll need to run a new permanent supply from the wiring centre to the stat position.
Or more sensibly, put your wireless receiver at the wiring centre and disconnect the cable running to the existing star position (once you've worked out which pair it is in the wiring centre so you can connect to the dry contact).
 
Maybe I am missing something but where does WiFi come into the system.

The existing thermostat appears to control the boiler by switching a wired link to the boiler.

The new Chinese device appears to control the boiler in the same way.

No WiFi between thermostat and boiler in either case.
 
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I may have made an invalid assumption- I assumed the Wi-Fi thermostat was a freestanding thing with wireless link to the base (the bit that requires power). It may of course be a thermostat controllable by An App :)
 
Yes, but where are you getting a permanent live and permanent neutral from? You mentioned no live terminals coming through but that brown wire could be 240vac live.
I will be drawing a new wire into the housing to power it up. The existing one is battery controlled. I put a tester on both wires and none of them are live, or so it appears. I will try again later today and feedback. To me it looks like the thermostat is a simple switch that completes the circuit when it drops below a temperature. Or am I being too simple?

I may have made an invalid assumption- I assumed the Wi-Fi thermostat was a freestanding thing with wireless link to the base (the bit that requires power). It may of course be a thermostat controllable by An App :)

Exactly that. It looks to me like a switch with a thermostat.

Maybe I am missing something but where does WiFi come into the system.

The existing thermostat appears to control the boiler by switching a wired link to the boiler.

The new Chinese device appears to control the boiler in the same way.

No WiFi between thermostat and boiler in either case.

As oldbutnotdead mentioned, the thermostat itself has the wifi element which is controlled by an app / timer program. I have a combi boiler so wouldn't need to control the boiler other than telling it to switch on CH
 
Testing between the 2 wires will probably give you the same potential. It states on the sticker 230vac switching, test between the live (brown) and an earth, or neutral point, you may find it’s 230vac. Yes it’s a switch the battery element will just power the unit and assist in the switching. Which boiler do you have?
 
To me it looks like the thermostat is a simple switch that completes the circuit when it drops below a temperature. Or am I being too simple?

Yes I have a few times wondered with a modern gas combi-boiler why we need a wall thermostat, and on/off switch with wifi could do the same job.

However it is down to what you can link to with the wifi. IFTTT can in some cases do what you want, but what happens if wifi goes down?

However there are two very different thermostats, there are OpenTherm and other similar methods which slowly turn the boiler output up and down, and there are on/off basic designed to turn off the boiler when warm weather arrives to stop the boiler cycling.

Location is important, to stop boiler cycling we place the on/off wall thermostat where it will remain warm over night and in a room normally kept cool, of course with no outside door, alternative heating and normally on ground floor, on a spring morning when likely to be a fine day we don't want it to fire up the boiler when latter in the day the house will likely get too warm, although hall does have outside door, it is often used for the thermostat as we keep halls cool, so can be set to 17°C and still allow central heating to run, so more likely to turn off boiler in warm weather.

But with the modulating thermostat it is likely placed in the main room.

There seems to be a problem getting people to use the TRV's to control rooms, and after living in my late mother's house with a modern modulating boiler I can understand why, I found it hard enough changing from °F to °C but *123456 marked on the TRV was about as much use as chocolate fire guard. So we had a lock shield valve on supply, and TRV on return which seems wrong way around, and some how your suppose to work out how to set them. Once a had a TRV marked in °C then I could set them, my head had current and target temperatures shown, so current above target close lock shield a bit and current below target open lock shield a bit and once set the TRV was spot on. And swapping back to *123456 I found 3¼ gave around 20°C and still worked spot on once the lock shield had be set using the one with °C marked on it.

However the whole idea of the TRV sending a wifi signal to a wall thermostat/switch to control boiler failed as I simply could not get them to talk to each other. Nest Gen 3 wall thermostat should have talked to the Energenie TRV but it was hit and miss. Since both are thermostats I simply set to same schedule so temperatures matched, the TRV was IFTTT, but I have never really got my head around IFTTT to control them.

So for wifi to work I would say wants the be the same manufacturer, so Hive wall thermostat and Hive TRV heads at least for important rooms likely will work well, but unless you can find a TRV to work with the wall switch then there may be problems.

I have only used the geofencing with Nest wall thermostat, although geofencing can be used with Energenie I have found once the Nest is turned down, the radiators don't heat up anyway, so no need for both to use geofencing, obvious really. It would depend how long the heating is turned down for, if for days then geofencing for TRV may make sense, but I think unlikely.

As to manually changing temperature from the phone, only time I do that is for cooling, I will look at room temperature reported on the TRV to decide if to turn AC on, but that is only time I manually use phone.

So for a 10 hour gap likely any geofencing switch would work, as you say all you want it to do is switch off heating when you leave, and switch it back on before you arrive home again, so any switch, maybe with a frost stat across contacts in case really cold would do the job.
 
I'm planning on replacing my existing danfoss tp4/5000 with one of the numerous WiFi thermostats available from China. There are a few different designs but the contacts are more or less the same.

Just want to clarify the following will work. Attached is a picture of my current thermostat with is battery operated so no live terminals coming through. As well as the wiring diagram of the new one "GC" drawing.

Can I replace this existing > new with:

2- 1
3 - 2

And then power it up using live / neutral?
Nope that is wrong, the two thermostat weres connect to 1&2 eitherway round, then :

N to 3
L to 4
 
Nope that is wrong, the two thermostat weres connect to 1&2 eitherway round, then :

N to 3
L to 4

I’m thinking he’s using the 2 - 1 and 3 - 2 numbered from the Danfoss? So 2 from Danfoss to 1 in GC, and 3 in Danfoss to 2 in GC, that’s how I took the clear as mud explanation anyway :LOL:
 
Testing between the 2 wires will probably give you the same potential. It states on the sticker 230vac switching, test between the live (brown) and an earth, or neutral point, you may find it’s 230vac. Yes it’s a switch the battery element will just power the unit and assist in the switching. Which boiler do you have?

I have an Ideal Combi ES35 boiler. Hmm some good points. I think you're right. That it is live switched. Which means there is already live there. First thing is first I need to establish if its live or not.
 
No that is the wrong wiring sequence you need GC in this pic and it is volt free (dry contacts because it is chinese )

GC.jpg
 
Testing between the 2 wires will probably give you the same potential. It states on the sticker 230vac switching, test between the live (brown) and an earth, or neutral point, you may find it’s 230vac. Yes it’s a switch the battery element will just power the unit and assist in the switching. Which boiler do you have?

So you were right I checked again and there are 236V when I connect up the two points using multi meter. Curiously though, I thought that would trigger the central heating on, but it didn't hmm



No that is the wrong wiring sequence you need GC in this pic and it is volt free (dry contacts because it is chinese )

View attachment 208556

Could you please instruct the correct wiring sequence based on the above new info. I seem to have a live coming into common and the neutral going back NO.
 
So you were right I checked again and there are 236V when I connect up the two points using multi meter. Curiously though, I thought that would trigger the central heating on, but it didn't hmm





Could you please instruct the correct wiring sequence based on the above new info. I seem to have a live coming into common and the neutral going back NO.
Wiring diagram GC, do not wire it any other way , or will be very expensive
 
I was using GC version. The question is from my old thermostat which terminals correspond to the new "GC" terminals...
 

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