combi boiler wiring diagram

[sime27]

Can 1 of you lot draw me a detailed wiring diagram for a modern combi boiler? (please include types of cable)

This must include switched fused spur off ring , external digital siemens time clock , external thermostat and 3 pole switch for isolation next to the boiler (live , neutral and switched live)

[simon_d]

sime27 wrote:

Can 1 of you lot draw me a detailed wiring diagram for a modern combi boiler? (please include types of cable) This must include switched fused spur off ring , external digital siemens time clock , external thermostat and 3 pole switch for isolation next to the boiler (live , neutral and switched live)

more importantly, why do you have to ask this. if your installing a boiler and not 100% of the wiring to the boiler, check the installation manual. (and if you can understand that, call someone who can)

otherwise ask your lecturer. dont expect others to do your work for you. what happens when your on your own?


asking the odd question that your stuck with, like your stuck with how the stat works etc is fine, but asking us to do YOUR work is not.

[sime27]

I only ever wired ones with internal controls with the fused spur outlet as the isolator.

never done 1 with external stats and 3 pole isolator so any help will be much appreciated

[sime27]

does this sound right?

3amp Spur off ring with 2.5 twin and earth
live neutral and earth out of that into the time clock to feed that
then live and neutral out from the same terminal for the permanent live to the boiler
the from the load side of the switched terminal of the time clock run 2 brown core and earth to the thermostat.
then from the outgoing side of the thermostat conect this to the switch switch wire of the boiler?

which then gives me live neutral and switched live at the boiler which i connect up into the 3 pole isolator..

[Steve]

I thought modern combi boilers have all this kit built in and all you have to do is run a bit of flex from the boiler to the FCU. (and an optional room stat)

[sime27]

not built in on this 1 mate as they having it fitting in a loft so external controls are needed

[RMS]

Does your boiler not have a wiring diagram in the installation manual showing the connection fo external controls, if not there should be a diagram showing the wiring of all the components internal to the boiler and you can then connect your prog. to suit.

[sime27]

yeah i know the wiring at the boiler end after the 3 pole isolator i have 2 flexs 1 is the supply live neutral and earth. the other is 2 core witch is switched live and neutral.

I just want to know if my side of the 3 pole isolator sounds right?

[simon_d]

sime27 wrote:

does this sound right? 3amp Spur off ring with 2.5 twin and earth live neutral and earth out of that into the time clock to feed that then live and neutral out from the same terminal for the permanent live to the boiler the from the load side of the switched terminal of the time clock run 2 brown core and earth to the thermostat. then from the outgoing side of the thermostat conect this to the switch switch wire of the boiler? which then gives me live neutral and switched live at the boiler which i connect up into the 3 pole isolator..

thats right. altho if you cant get a 3pole switch, use 2pole (make sure it doesnt have a neon) and dont switch the neutral (its already DP switched earlier down the line)

and you best use 3core and earth to stat - some require neutral/