Mains to boiler wiring?

[wombats]

I am getting a boiler fiited within the next 4 months by a proper installer.
What i would like to know is if someone could do me a wiring diagram showing from mains (or CU) to the boiler and any other things it would goto. I am in the process of refitting my kitchen and would like to get rid of the old wiring for the existing broken boiler and timers and emersion switch.

What wiring would have to go to the new combi boiler (which will not be situated in the kitchen)?

What i am wanting to do is ( why i have the floorboards up) lay down the new cables needed for the new boiler so that they can just be connected up when the boiler is installed.

Can anyone help please?

 

[Chri5]

Could you confirm if all the controls will be at the boiler position ?

Combis (like any boiler) could have wiring requirements for a remote ch thermostat and may also have feeds to a 7 day timer to activate the ch (if you want the controls remote).
Reason for having a remote timer could be that the boiler site is remote such as loft, high level position or tucked away in a area that is a PITA to get to.

As for the main power requirement for the boiler, a 2.5mm cable as a radial from the CU will cover the load requirement. Fuse rating at CU subject to boiler demand requirements (see boiler manufactures spec) and as a further precaution a switched fused spur for isolation at the boiler, again the fuse in the spur to be determined via manufactures spec.

 

[wombats]

Thanks for that info Chri5.

The main control will be at the boiler postion, think it will be a remote ch thermostat and programmer which is wireless so the main body of wiring will be near the boiler.

Will the 2.5 need to be a loop or can a single wire run straight from the cu to the boiler position?

 

[Chri5]

A radial circuit (single cable run) for feed between boiler and CU.

Subject to existing load on the local ring circuit, you could run a spur although that would mean the boiler isn't on a dedicated circuit.

 

[wombats]

Thanks again Chri5, I will just lay down a single 2.5mm twin & earth to a switched fused spur and then leave the rest to the sparky for when the boiler is installed. With a bit of hope he won't have to mess up my walls having to run more wires.

Thanks again Chri5 your help was much appreciated

 

[mattylad]

Why not ask the person thats going to be installing the boiler exactly what they require?

 

[wombats]

I can't ask the person installing the boiler as i don't know who it is going to be yet as it will be done in the next 4 months and i have no control who the contractor will be as i am not paying for it.

 

[ColJack]

put in a single backbox with 2 20mm conduit drops to it ( plastic will do ).. that way the walls can be finished and any control wiring put in afterwards..
you'll obviously have to position the box and conduits to suit the position of the boiler.

 

[wombats]

Sorry for the late reply to your answer ColJack.

As the plaster on the walls to where i would need to fit the box is not that thick would putting 2 16mm conjuit drops in be enough?

 

[ColJack]

just chase into the brick for the extra depth..
it's up to you.. do you think that 16mm conduits would be big enough for any control wiring you might need?

would oval conduit be better?

 

[Chri5]

Just to be clear you must understand the wiring requirements:-

a) Obvious 230v supply for boiler power
b) Unknown cables to a controller / wiring centre / thermostat etc

Firm up your requirements for the bolier, google the instructions and confirm the wiring (or else).

Remember the cables need to go the whole route between boiler and the devices you intend to use.

Normal format is a 5 core wire between bolier and the location of a wiring centre, from there you feed to the timer / controls / thermostat. Systems vary.

Here's a basic example, yours would be the top diagram