Upgrade to Nest Thermostat E from Honeywell R6660D

Hello guys, I am trying to figured out the wiring on my current Honeywell Receiver which works fine with my wireless Honeywell CM927.

I am confused with the current wiring of my receiver - please see pictures which I will attach:

current wiring:

N blue cable (I guess neutral)
L brown cable (I guess live)
L brown cable (this is where I get confused as this is a small brown cable connecting A to L like a loop cable)

A small brown cable coming from L as above
B green cable (I guess open wire?)
C empty
D empty
E empty

on my new nest heat link I need to identify the common and open wires from my current setup so I can carry on.

any help would be appreciated.

regards,
Seb.

 

One more picture if it helps

 

Couldnt be simpler but never go by wire colours on a heating system

honeywell Nest

N to N
L to L
Link L to 2
C to 3

 

Thanks mate. What do you mean C to 3? On my current setup C is not connected to anything?

 

If anyone can just confirm what’s the common and open wire on my current system that would be great. I want to make sure I understand current wiring to proceed with the next steps. Thank YOU in advance

 

2 is Com
3 is NO (normally open)

Typo should be B to 3

 

The two L terminals on the Honeywell reciever are linked together internally. The loop from L2 to A means that terminal A always has 240Vac on it. When the switch in the receiver closes terminal B (switched live) provides 240Vac to turn the boiler on.

Terminal C is used for cooling systems.

 

Thank you so much for all the answers, things are starting to get clear in my diagram mind

As per what D_Halisham said I will then use the brown cable currently connected to L1 as my common wire and the cable connected to B my open wire, therefore the small brown cable connecting L2 to A can be just removed.

I tried to draw what I will be doing just to confirm if anyone can please confirm it that would be great. I don’t want to try anything before I am 100% as wife already threatened me with a divorce depending on the outcome....



Read more: https://www.diynot.com/diy/threads/...e-from-honeywell-r6660d.537310/#ixzz6BOCMxxGg

 

Drawing of what to do next with wires

 

No, you're not paying attention.

N to N
L to L
Link L to 2
C B to 3

 

yes it is

 

you have got them wrong that is B&C not A&B

 

sometimes wonder why we bother mate the B that is actually C

 

No, it isn't. Either way C is normally closed.

 

EFLImpudence
thanks a lot for all the spot on info however do you mind clarifying when you said:

N to N
L to L
Link L to 2
€ B to 3

my new Nest Thermostat only requires two cables (Common and Open) therefore N and L1 won’t be used from what I understood - I will use the terminal blocks to isolate them.

Link L to 2 means I will connect L to Common socket on nest?

€ B to 3 means I will connect B to NO socket on nest?

I didn’t understand what numbers 2 and 3 meant on your earlier post. I will post a picture of how Nest thermostat sockets are arranged.





Read more: https://www.diynot.com/diy/threads/...e-from-honeywell-r6660d.537310/#ixzz6BOY4TEru