Discuss Worcester Bosch wiring advise please in the Central Heating Systems area at ElectriciansForums.net

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J.C.E

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A mate of mine asked me to look at the wiring of a boiler in a flat he is doing up.

As I told him- I am hopeless with central heating.

the boiler is a WB- guessing a combi because there is only a boiler and room stat-no tank, cyl stat etc.
the rads have 'trv's' on them- not sure what these actually are- just know their there lol!

the boiler has a L,N,E from a 5a spur and then there a 3core flex coming out of it that has just been cut.

the Honeywell room stat is in the lounge the other side of the wall.

do I just need to connect the L and N from that 3core to the r.stat?
maybe before it was cut the earth was used as a live conductor too? (Wrong I know...)

any ideas will be great

joe
 
Hi mate really easy!!

L N E from fcu to boiler... Then from Ls on boiler to roomstat then return from roomstat back into Lr on boiler. Roomstat will require a N.

Possible to wire a 5 core flex into boiler and run roomstat cable into the fused connection unit.
 
A mate of mine asked me to look at the wiring of a boiler in a flat he is doing up.

As I told him- I am hopeless with central heating.

the boiler is a WB- guessing a combi because there is only a boiler and room stat-no tank, cyl stat etc.
the rads have 'trv's' on them- not sure what these actually are- just know their there lol!

the boiler has a L,N,E from a 5a spur and then there a 3core flex coming out of it that has just been cut.

the Honeywell room stat is in the lounge the other side of the wall.

do I just need to connect the L and N from that 3core to the r.stat?
maybe before it was cut the earth was used as a live conductor too? (Wrong I know...)

any ideas will be great

joe

Some roomstats only need 2 wire, others need 3 wires.

The difference is the 2 wire stat is electronic and is very sensitive to temp. changes so the 2 wires are Perm. live (from boiler) and Switched live back to boiler to fire it when stat calls for heat.

The 3 wire stat is mechanical and has a heater (called an Anticipator) inside it to improve its sensitivity and this needs the perm. live, the switched live AND a neutral for the anticipator. It can work without the neutral but you'll get ridiculous variations in room temperature.
 
Hi mate really easy!!

L N E from fcu to boiler... Then from Ls on boiler to roomstat then return from roomstat back into Lr on boiler. Roomstat will require a N.

Possible to wire a 5 core flex into boiler and run roomstat cable into the fused connection unit.

What numbers do i use on rstat? For L SL and N?
 
Bingo

n 2
ls 4
lr 3

your wrong there with the live's 1 is ls and 3 is lr

Worcester Bosch wiring advise please {filename} | ElectriciansForums.net


and there very easy to wire, you will be fine just dont over tighten the pcb terminals i have had a few from the factory snap/ fall out bad solder joint :)
 
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