Installing nest thermostat, help please

26 Aug 2016
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United Kingdom
Apologies, posted this in elctrics, meant to put it in heating. So i have tried to move it or delete it without success.

I have an ideal classic boiler and a lifestyle LP241 programmer, no thermostat on the system. I can turn heating and water on and off separately or together.

I want to swap the programmer for the nest heatlink and then control it with the nest thermostat third gen (which says it can control hot water).

My existing programmer has the following wires.


The heatlink appears to ask for four wires, hence my confusion. It asks for CH Call for heat (i presume this means on), CH common, HW call for heat and HW common. On the basis that hte old programmer had only heating on, i have tried not having a heating common - but nothing works. What am i missing?

Thank you.


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Aha, you may have solved the problem. I will swap them and come back in a minute.
Thank you, hopefully
Last edited:
Alas, it still doesnt work (but thanks for your interest so far).

Here is how i thought i should transfer the wires, although it has not worked. If anybody can see what i have done wrong, i wouuld be really grateful.

My first try
Old LP241. New nest
CH on. CH call for heat
HW on. HW call for heat
HW off. HW common

After reading the above post i tried the following, but no good. I must have misunderstood your comment?
Old LP241. New nest
CH on. CH common
HW on. HW common
HW off. HW call for heat
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Ah sorry, I missed the HW OFF connection.

Therefore you do not have enough terminals on the nest.

What sort of boiler and system do you have?
Thank you for keeping on trying to help. If i can check i am about to do the right thing then....

What was Will now be
L241. Nest
HW OFF. HW satisfied

Come on guys it's only a Nest stat!
N Neutral
L Permanent live
1 Not used
2 Connect a wire link to the L terminal
3 Connect your Heating on wire
4 Connect your HW off wire
5 Connect a wire link to terminal 2
6 Connect your HW on wire
Ok, so i hadnt tried any wire links. Will try your version echo, you seem to be ok with it efl :)

Cross fingers, il lreport back soon, off to find some wire....
I've just scrolled down and noticed they do actually provide a wiring diagram in the manual!
nest y.png
You are true gentlemen, both of you.

I couldnt make head or tail of the diagram, as i couldnt correlate it to the on/ off wires i had.

Thankd guys, i can havea bath now :)

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