Boiler Fused Connection Unit location

[Michaelwgroves]

I need to wire a new system boiler, the obvious place to put the supply is with the control unit which powers the boiler. But should the FCU be next to the boiler in the same way any isolation switch would be located close the load. This would still power control unit, but also need cable coming back to boiler which would not be ideal. But then you could argue FCU is no longer local to pump/valves etc.
I can't see anything in OSG about this?

 

[buzzlightyear]

no, where the control unit is all feed from that's where FCU should be

 

[Michaelwgroves]

Sorry I don't understand response, to be clear S Plan wiring diagram terminals 1-3 is supply, with terminals 1,2 & 10 supplying boiler ?

 

[telectrix]

where does the supply come in. to the boiler or to the controller?

 

[buzzlightyear]

have you got the s plan to hand !

 

[buzzlightyear]

I have put this on for you .

 

[Michaelwgroves]

Supply comes into controller

Yes I have S Plan in front of me

 

[telectrix]

FCU by controller then, as long as it kills the supply to the boiler as well. label on boiler to indicate the location of the FCU.

 

[buzzlightyear]

Supply comes into controller

Yes I have S Plan in front of me

work off the plan and you cant go wrong ,the idea when any body come behind you in the future
it they can say what a good spark that put this in and I'm not blowing smoke up you a**.

 

[Michaelwgroves]

Thanks guys, yeah label on boiler covers it for me.

 

[Leesparkykent]

New install the SFCU normally goes next to the boiler. If you install it in the cylinder cupboard then ideally the boiler would have an isolator installed adjacent. If the boiler require LNE and switched live then you would need a triple pole switch/fan isolator next to the boiler. Most new builds are specified SFCU next to boiler with programmer in that location as well.

 

[Michaelwgroves]

Does it depend on boiler type, for combi I would agree, but in this instance it's a system boiler so have controller next to cylinder, so as mentioned above it seems to make more sense to have with controller.

 

[Octopus]

I would say it should be either near the boiler OR near the controller.

As far as I know there are no regulations that say where it must be

 

[buzzlightyear]

not in my house boiler down with programmer upstairs controller next to hot water cylinder with the FCU.

 

[Octopus]

Thanks guys, yeah label on boiler covers it for me.

Why? There are too many labels imho

 

[Madocks]

Common sense would suggest if there's no isolation at the boiler then the isolation is with the valve controls up in the airing cupboard

Surely any spark would check this and prove dead?

 

[Leesparkykent]

As I said In most newbuilds with a fully pumped system (boiler, cylinder, S-plan, y-plan etc) the SFCU is next to the boiler and the two channel programmer for heating and hot water is normally located next to the boiler. Programmers are normally located in airing cupboards on retrofit systems due to ease. Any system from scratch I would locate the SFCU next to the boiler rather than the cylinder cupboard. I believe gas safe require an isolator next to the boiler. So if you install the SFCU remote from the boiler then you should install an additional isolator next to the boiler...which you wouldn't need if you installed the SFCU next to the boiler.

 

[buzzlightyear]

quick get the handbags boys this is going to get ruff.

 

[Octopus]

My controller is wifi, so no fcu near that

 

[buzzlightyear]

horses for course I say, has long has your happy about the job.

 

[Octopus]

As I said In most newbuilds with a fully pumped system (boiler, cylinder, S-plan, y-plan etc) the SFCU is next to the boiler and the two channel programmer for heating and hot water is normally located next to the boiler. Programmers are normally located in airing cupboards on retrofit systems due to ease. Any system from scratch I would locate the SFCU next to the boiler rather than the cylinder cupboard. I believe gas safe require an isolator next to the boiler. So if you install the SFCU remote from the boiler then you should install an additional isolator next to the boiler...which you wouldn't need if you installed the SFCU next to the boiler.

My boiler, cyclinder / tank , wiring centre and fcu are in the airing cupboard ....

 

[buzzlightyear]

My boiler, cyclinde / tank

don't say Murdoch you have challenger tank
next to the FCU has well.

 

[Leesparkykent]

My boiler, cyclinder / tank , wiring centre and fcu are in the airing cupboard ....

We've just done 80 houses for persimmons and the spec was boiler, SFCU and two channel programmer in utility. Same spec also on crest Nicholson and Abbey new homes.

 

[Octopus]

We've just done 80 houses for persimmons and the spec was boiler, SFCU and two channel programmer in utility. Same spec also on crest Nicholson and Abby homes.

Our utility wasn't built when the house was refurbished .....

 

[buzzlightyear]

We've just done 80 houses for persimmons and the spec was boiler, SFCU and two channel programmer in utility. Same spec also on crest Nicholson and Abby homes.

that new homes, not old manors.

 

[Leesparkykent]

that new homes, not old manors.

Yeah I know, I wired them

 

[buzzlightyear]

what ever the spec says the it ok ,but to challenge about the spec some body starts crying like the builder .

 

[Octopus]

This is a classic example where more recent "good practice" can not be applied to older installations and complete numpties go around condemning installations .....

 

[Leesparkykent]

when we was doing energy company obligation work/eaga work many moons ago they didn't mind the SFCU in the airing cupboard but was also specified that if that was the case then an isolator was also needed next to the boiler. I've always thought this could of been something to do with gas safe.

 

[Ian1981]

When we do new builds the spur and programmer is required to be next to the boiler, which is then fitted with a 600mm housing cupboard as specified.

 

[Michaelwgroves]

I’ll let you know what the gas safe guy says when he visits.

 

[davesparks]

Modern boilers sometimes require that the feed go to the boiler first, and the rest of the control system be powered from the boiler. This ensures that if the fuse in the boiler blows the whole circuit including switched live to the boiler goes off.

So checking the manufacturers instructions for the boiler would be a good place to start.
asking the plumber is less likely to get you the right answer as they rarely know, or care, about the electrics.

 

[Midwest]

The FCU is for the safe isolation of the system, generally for maintenance. Us 'very intelligent electricians', having need to carry out maintenance on any part of the system, would know how to safely isolate the system and verify that. A Gas Safe engineer carrying out the annual service on the boiler, is of course not as intelligent as us electricians , so having the FCU next to the boiler would seem more appropriate, as that seems to form the heart of the system as a whole and in the control of the engineer IMO. Of course you could have the FCU elsewhere, but if you didn't want some numpty, replacing the fuse in your remote FCU and switching on, while you're fiddling around inside the boiler, then its best to have it local to the boiler.

I note some boilers manufacturers, have the supplier into the boiler, then an outgoing feed to controls, with a switching wire back into the boiler. So would be easier to have FCU next to boiler anyhows

 

[Toneyz]

Does it depend on boiler type, for combi I would agree, but in this instance it's a system boiler so have controller next to cylinder, so as mentioned above it seems to make more sense to have with controller.

And as Lee posted install a plain three pole isolator labelled up boiler adjacent to it.

 

[snowhead]

but if you didn't want some numpty, replacing the fuse in your remote FCU and switching on, while you're fiddling around inside the boiler, then its best to have it local to the boiler.

Your FCU should be lockable.

 

[telectrix]

the FCU should be inside the flue, same as the stupid kitchen fitters insist on with cooker hood isolators/FCUs. hidden out of sight so it does not detract from mrs. bloggs's shiny new kitchen.

 

[Midwest]

Your FCU should be lockable.

Yep like Mae West's chastity belt.