Nest 2nd Gen Learning Thermostat (Fitting)

[LesAshmore]

Hi all I have a Worcester R40 Combi Boiler with a Salus RT500RF remote thermostat, I have decided to change the stat to a Nest 2nd Gen Learning thermostat and I am not exactly sure on the Link Wiring, On the Salus RX I have 4 wires a Blue (N) and a Brown (L) I also have a Black which is linked to the Brown (L) and a Grey which is fitted into the SL (on) on the Salus receiver, Would I be correct in assuming that the Blue = N Brown = L on Nest Link and then there is a link wire between L & 1 and Black is then also connected into 1 and then the Grey is fitted to 2 on the Nest Link Please

 

[stem]

Your text regarding the current wiring is not clear.

I also have a Black which is linked to the Brown (L)

A link connects two points, you only mention one 'L'. Where does the other end of the link go? I would expect it to link L and COM. making the Salus receiver wiring as below:

'L' = Live from supply
'N'= Neutral from supply
'N.O.' = Switched Live (on) to the boiler
'L' terminal linked to 'COM'

If the above is the case, the Nest will be:
'L' = Live from supply
'N'= Neutral from supply
'3'= Switched Live (Call for Heat) to the boiler
'L' terminal linked to '2' (Common)

If what you have is different, post back. I'm slightly puzzled because

a Grey which is fitted into the SL (on) on the Salus receiver

I haven't seen a Salus with a terminal marked Switched Live, it's normally N.O.

 

[LesAshmore]

Hi Thanks for reply, The Link wire connects between the L and COM on Salus as you state, Sorry about that, So basically the Nest is the same as the Salus with dif names as I thought, Thank you so much.

 

[LesAshmore]

This is a Pic of Rear of Salus

 

[LesAshmore]

Hi Stem, I noticed that on my pic That there is a Link to COM which also has the Black wire into the COM, Will this black wire become redundant or does this need connecting into the 2 (Com Link) ?

 

[stem]

To ascertain that, you would need to find out what the other end of the black wire is connected to. But it will probably need reconnecting. It may be the permanent live supply for the boiler.

I've not seen a Salus RT500RF like that before, the current models are different, hence my comment about not having seen a terminal marked "Switched Live" before. The wiring convention is the same though, so no worries.