wiring a combi with timer and fcu

[solomongrundy]

Can timer and fcu be remote from boiler?- as in about 12 feet below in kitchen? I will obviously mark up fcu.
How does cabling go. My boiler has the dodgiest cabling- a mix of flex and T+E.
Two T+E cables exit base of boiler -one down into the timer. The other connects via some insulated tape to flex which then also enters timer. Flex exits the timer into a fcu. T+E leaves fcu for C Unit (via a couple of junction boxes).
Am i right in thinking i can use 2.5mm T+E and heat resistant flex and a 15A Type b mcb?
Any advice appreciated.

 

[Gasguru]

No problem having the clock etc remote from the boiler.

Do not use twin/earth cabling to the boiler. It's too rigid and if it connects to the board the solder joints can fracture.

Only use round 0.75mm heat resistant pvc to connect to the boiler.

Either use a couple of 3 core cables or ideally multicore.

The fcu should have a 3 amp fuse and does not need to be a dedicated circuit from the consumer unit.

You can use standard overflow pipe and pipe clips to protect the wiring up to the boiler.

Is there no room thermostat?

 

[baz1968]

It's always a good idea to have an isolator near the boiler for local isolation for maintenance etc. Any flex used in or around high temperatures should be heat resistant, such as butyl sheathed or similar.

 

[solomongrundy]

thanks for replies. Much appreciated

So both cables from lower part of combi should be flex?- 0.75mm
Why are there 2 cables from combi to timer? - is it as a ring circuit of sorts? - one of which leaves combi as T+E and changes to flex to enter timer. the other is T+E all the way. then one flex from timer to fcu and T+E from fcu to consumer unit.

There is no room thermostst.
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