Nest Thermostat 'E', not turning EcoTec Pro off, house like a sauna!

[picasso]

The cables to the nest must be live as the circuit wont complete otherwise as the programmer doesnt switch on.

What ? the call for heat starts at the programmer and is then sent to the nest, when the nest switches on temp fall the boiler comes on.

 

[ianmcd]

the programmer starts the circuit, the nest interrupts it, the nest is simply a switch, nothing more nothing less, do as suggested and remove the batteries and see if the boiler still comes on

 

[Pd-legalcbs]

The boiler has always come on whether there's batteries in or out of the heat link

 

[flameport]

The boiler has always come on whether there's batteries in or out of the heat link

There are only two possibilities.
Either the wiring at the heatlink is incorrect
or more likely, the wiring isn't connected to anything.

Given this:

I believe my old thermostat never worked

then it's very likely that the old thermostat wasn't connected to the boiler. Probably disconnected and just left on the wall when an older heating system was replaced with a combi.

As it's a combi boiler, the old programmer needs to be removed and the new Nest heatlink installed in it's place.

 

[ericmark]

Looking at the pictures there is a supply to boiler then three core and earth going to programmer, and at programmer a three core and earth, unless there is a wiring centre some where between the boiler and the programmer then can't see how anything is connected to the system as well as programmer?

Had same here, and it asked the question what did the previous owners do? To switch on central heating needed to turn on programmer did not matter if DHW or CH as only two wires so both options did the same, then out of house and into garage under house and plug in the pump. It seems the heating did not work after garage turned into flat.

It seems the programmer only does CH in your case, so simply replace programmer with Nest.

 

[ianmcd]

The boiler has always come on whether there's batteries in or out of the heat link

Then it is not wired correctly

 

[Pd-legalcbs]

There are only two possibilities.
Either the wiring at the heatlink is incorrect
or more likely, the wiring isn't connected to anything.

Given this:

then it's very likely that the old thermostat wasn't connected to the boiler. Probably disconnected and just left on the wall when an older heating system was replaced with a combi.

As it's a combi boiler, the old programmer needs to be removed and the new Nest heatlink installed in it's place.

The home is relatively new (2008). This has always been the heating system. The old thermostat was connected. I cant say for sure but I dont believe adjusting the old thermostat ever did anything but my partner believed it did.

There doesnt seem to be any guidance in replacing the programmer directly with the heat link, it just states the programmer needs to remain and stay on.

 

[Pd-legalcbs]

Looking at the pictures there is a supply to boiler then three core and earth going to programmer, and at programmer a three core and earth, unless there is a wiring centre some where between the boiler and the programmer then can't see how anything is connected to the system as well as programmer?

Had same here, and it asked the question what did the previous owners do? To switch on central heating needed to turn on programmer did not matter if DHW or CH as only two wires so both options did the same, then out of house and into garage under house and plug in the pump. It seems the heating did not work after garage turned into flat.

It seems the programmer only does CH in your case, so simply replace programmer with Nest.

Definitely nothing else connected to the system, will have to look into whether replacing the programmer can be done.

 

[stem]

Nice try with the diagrams but there's a lot of info missing. A wire always has two ends, so there will always be an even number. Your diagram has 3 brown ends, where's the 4th end? Same for the black wires, and there's only 1 grey end. Anyway, this is how the Nest should be connected. Everything else goes.

 

[Pd-legalcbs]

Nice try with the diagrams but there's a lot of info missing. A withe always has two ends, so there will always be an even number. Your diagram has 3 brown ends, where's the 4th end? Same for the black wires, and there's only 1 grey end. Anyway, this is how the Nest should be connected. Everything else goes.

View attachment 186181

Thanks for the diagram, where would the programmer fit into this? The grey and black wires are present behind the thermostat/heat link but with a small brown and blue sheath (?) on each one respectively. Ill fix them as you have llustrated and cap off the remaining brown wire.

All the wires on my diagram are the only wires present behind the devices, the images show what is attached. If any are missing then I've no idea where they would be, the blue neutral doesnt appear behind either the heat link or programmer for example.

 

[Pd-legalcbs]

....barring the earth wires!

 

[flameport]

where would the programmer fit into this?

In the bin.

The Nest is all that's required. It's a programmer and thermostat all in one device.

 

[Pd-legalcbs]

In the bin.

The Nest is all that's required. It's a programmer and thermostat all in one device.

This is a Nest Thermostat 'E'. It replaces the thermostat only. The programmer is left on as instructed in the setup guide.

 

[stem]

You don't need a programmer because the Nest-e provides both time and temperature control in the one unit. The programmer becomes redundant, which is why you have the instruction...

The programmer is left on as instructed in the setup guide.

...So the programmer becomes a useless ornament on your wall that has no function.

If your system was correctly installed and working properly, the easiest DIY way of installing Nest-e it would be just to swap the thermostats over and leave the programmer 'on' 24/7 as per the set up guide. However, as your installation has issues that need rectifying, best to start from scratch, and dump the ornament.

If it was a new installation, it would be done as per my diagram. No one would go to the trouble of buying and wiring in a programmer to then leave it permanently on.

 

[ericmark]

In the boiler you show two flexible cables, one clearly feeds the boiler, the other goes to some control, I would guess black goes to pump and white does everything else, I looked at the wiring diagram I found earlier and is seems wrong one.


However the 5 core flex some where becomes three core and earth flat grey cable, so some where you have missed something.