Wireless thermostat wiring

12 Mar 2014
Reaction score
West Glamorgan
United Kingdom
Hi all, due to finding out my thermostat wiring has been lost behind the walls, I've been told to have a look at wireless thermostats.
I have the Wiring diagrams for both sides but am a little lost...could anybody shed some light or should I get a pro in?

Boiler has:

LR switched live
LS live
NS neutral
N 230v mains neutral
L 230V mains live

Stat receiver has:

N neutral
L live
HW on
HW off
CH on

Any ideas?

Many thanks
Sponsored Links
Can you please tell us which boiler you have and what kind of system it is .is it a combination boiler or conventional or on Honeywell S or Y plan

You are very vague with all your information unfortunately and my crystal ball has been sent away for polishing :D :D
Sponsored Links
I do apologise... Its a Worcester Greenstar 25Si Combi boiler with Grant RFTKIT DOC20 programmable room thermostat.
On a combination boiler you do not need a control over your hot water ,this is done by turning the water on and off

You need a single channel programmable room stat
Oh dear.

In the stat manual it says that for combi boilers there must be no connection made from terminal 4 (hw off). There'd be no way of retrofitting the two together would there?
That's not a problem, don't make a connection to terminal 4. you don't need control of your hot water as previously mentioned.

So, the 'CH on' terminal of the thermostat is the switched live for the control of the central heating. It should be connected to the LR (Live Return) terminal at the boiler. There should not be any connections to the hot water on or off terminals.

Connect a L and N to the appropriate terminals at the thermostat and you are good to go.

So to summarise, all you need is:

Thermostat neutral terminal = Ns (neutral supply) at boiler

Thermostat live terminal = Ls (live supply) at boiler

Thermostat terminal CH on = LR (live return) at boiler

I'm not familiar with the RFKIT, but based on the info you give, whilst it will work, you seem to be replacing just a thermostat with a programmable thermostat (which is a thermostat and programmer combined) if so, and your boiler has an integral programmer fitted, you need to set the Central Heating function to be permanently 'on' at the boiler, and let the programmable thermostat control the on/off times and temperature. In addition the RFKIT also has hot water control which you don't need.

Or alternatively, I agree with Happyplumber. instead of the RFKIT just install a basic wireless thermostat without a programmer function.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links