Replacing Drayton LP112 with Nest 3rd generation

[LenBeach]

Hi all. We’ve just moved into a new house which is a full renovation project. We currently have a Drayton LP112 programmer and a traditional dial thermostat. I’m planning to install my Nest 3rd generation and thermostat.

The thermostat will be powered using a plug in power supply so that it can be positioned in the most effective spot in the house.

My wiring setup is as follows:
Thermostat:
N - 1 (wire)
L - 1
3 - 1

Programmer:
N - 3
L - 2
1 - 1
3 - 1
4 - 1

To decommission the thermostat as a temporary measure, move 3 over to live keeping the live in place.

To swap the programmer:

I already have 2 & 5 bridged with the live from my previous installation.

Live and neutral are self explanatory and move over from the Drayton to the Nest.

Drayton HW OFF 1 moves to Nest 4 HW satisfied

Drayton HW ON 3 moves to Nest 6 Hot water call for heat

Drayton CH ON 4 moves to Nest 3 Heating call for heat

Have I missed anything?

Thanks in advance all.

 

[Johnmdc]

That all looks correct.

 

[LenBeach]

That all looks correct.

Top man. Thank you.

 

[ericmark]

It seems odd, I have moved Nest Gen 3 to Drayton Wiser the reverse to you.

The thermostat will be powered using a plug in power supply so that it can be positioned in the most effective spot in the house.

I wonder how I would do that? The boiler is battery backed, so want either the thermostat to be battery powered or take the supply from the same point as the boiler, the two wires from the Nest Hub to Nest thermostat arrive in the hall, so Nest was tired to hall. This is where the Wiser worked better, the thermostat battery powered, so could put in the living room.

I was going to experiment around the room, two radiators at 90º to each other, so uncertain of thermals within the room, but got so odd results, found the cause, cat sleeping on the thermostat, so had to fit to wall.

Mother house also had a wireless thermostat, and also tried to find the best place. Found on her coffee table worked best. It was a problem due to morning sun through the bay windows.

But reasonable compromise was at the side of the radiator around 6 inches off the floor, i.e. the TRV (thermostatic radiator valve) but the problem was getting the boiler to run when required, so ended up with two wall thermostats in parallel.

This house same problem, in fact worse, the boiler does not modulate, so the TRV causes a sine wave, as it opens, but no water circulating the report shows it did not reach target as boiler turned off. Wiser also shows what has gone on, not perfect, but reasonable. And like Nest Gen 3 a learning thermostat, so likely will improve. But Nest how is that going to help, no record of temperature, just how long it turned on every day, totally useless, boiler ran far longer than it said, as three other thermostats, there is old dial type for down steps in the flat, hardly used, and the Wiser monitors both living room and Wife's bedroom, and Nest does the hallway. Power cut and bedroom thermostat stops working, as the signal booster is mains powered, but the other two Nest and Wiser will still work.

I had hoped to use the Nest temperature sensor, but one not released for UK, and it seems in the USA they don't work too well either

so I have given up with Nest, and it is just a back-up so if battery becomes discharged on Wiser, I will get some heat into the house, but all in all Nest rather useless as a thermostat, as a control device Nest works well, we love our Nest Mini's, they turn lights on/off, set the temperature with both Wiser and Nest, but Nest thermostat is rather useless.