y plan heating system

[biggles]

Hi im wiring a y plan heating system which ive done before a few times but cant seem to get my head around it. A few questions really. Q1 does boiler supply come from wiring centre with fcu close by or need its own circuit from c.u. via fcu. Can wiring centre come from fcu of ring circuit (would that be ok to bs7671) And am i right in thinking the cylinder needs its own supply from cu via 20a dp switch. Sorry long day brain just wont work.

 

[biggles]

sorry a bit more, should i send 230v supply to wiring centre and feed boiler from there with local fcu valves pumps etc.

 

[Dan23584]

Does this help at all?

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[Dan23584]

You are right with the immersion heater having its own supply from the cu via 20A double pole switch.

 

[GLENNSPARK]

is it an imersion heater? If so then supply it in the normal way (2.5mm radial...16A MCB). the salamander box on an FCU with the cylinder stat and the room stat 3 way port etc.....

 

[biggles]

ahh thanks guys thought i was on right track. and thanks dan got that diagram but it confused me. LNE to boiler from wiring centre thats fine but isnt the switched live missing. i was thinking i would need to have at least a 3 core and earth cable to boiler am i right in saying that.

 

[biggles]

oops i mean 5 core LNE. hot water switch wire central heating switch wire. Connected inside boiler also doesnt show that on diagram or am i being a complete plank. Sorry got to price for this tommorow.

 

[GLENNSPARK]

2 core to the cylinder stat....3 core to the room stat......

 

[biggles]

I guess my question is how many cores to boiler. Thanks in advance.

 

[topquark]

I guess my question is how many cores to boiler. Thanks in advance.

I normally run 5 core heat resistant from the wiring centre to the boiler (whether it needs the extra cores or not).

 

[Guest123]

As a minimum I'd recommend a 4 cores, this will give you a permanent live, a switched live a neutral & an earth.

Check boiler instructions regarding circulation pump as if it is external to the boiler you may need a cable from the boiler to the pump as some boilers control the pump directly rather than via the wiring centre.

Only one switched live to the boiler from the wiring centre will be needed as both CH & HW use the same one.

 

[GLENNSPARK]

And what i should have pointed out earlier guys was 3 core to the room stat and 3 core FLEX to the cylinder stat...sorry guys...

 

[biggles]

thats what i was thinking and am going to do. I got it now brain finally working. Thanks all who helped me there. Sometimes just need to chat about it to see the light...............