boiler control wiring and wet UFH wiring

[J.C.E]

Afternoon
Starting a rewire tomorrow on which the build wants me to do the control wiring (i have never done it and usually just do up to the spur)

I will be subbing the controls 2nd fix out to someone that can do it (and shadow over his shoulder with a note pad)

i assume it is likely going to be a system boiler (s or y) and I think the boiler/2port/3port, HWC programer are going in the garage

and the wet UFH manifold is going in the under stairs cupboard (i think the builder said there will be 2zones on this just for the ground floor

if my assumptions are correct above (I know i need to know for definate 1st etc)

Boiler controls
1st fix wiring-wise- i just need to get a 3core from boiler position to however many room stats they have for the boiler heating (likely 1 or 2 positions)

and then obviously my spur

then all the other control wiring can be done at 2nd fix stage as all local to boiler

UFH controls
again for 1st fix stage only need my 3core from the manifold position to room stat positions and spur- then all other wiring can be done at 2nd fix stage as local to the manifold?

do i need any other wiring put in place between the boiler and manifold positions?

any 'general' advise would be great at this stage as I know i am not being very specific yet!

 

[Leesparkykent]

You would normally wire the UFH thermostats back to the manifold position where you'll have your UFH wiring centre. You would then take a 3 core + earth from manifold/UFH wiring centre back to the Wiring centre where the cylinder and 2 port valves are etc. The radiator circuit thermostat would run back to this wiring centre aswell, not the UFH wiring centre.

 

[J.C.E]

You would normally wire the UFH thermostats back to the manifold position where you'll have your UFH wiring centre. You would then take a 3 core + earth from manifold/UFH wiring centre back to the Wiring centre where the cylinder and 2 port valves are etc. The radiator circuit thermostat would run back to this wiring centre aswell, not the UFH wiring centre.

so as thought-
3core/e from ufh stat to where manifold is
3core/e from CH stat to where boiler is

then have another 3core/e between the two wiring centres
(what is this 3core for?)

then all other wiring can be done at 2nd fix

 

[Octopus]

Hard wired room stats?

 

[Leesparkykent]

so as thought-
3core/e from ufh stat to where manifold is
3core/e from CH stat to where boiler is
Yes
then have another 3core/e between the two wiring centres
(what is this 3core for?)
LNE and switched live.

then all other wiring can be done at 2nd
fix

Yes if you can do it surface. If it's all in a dedicated area for example.

so as thought-
3core/e from ufh stat to where manifold is
3core/e from CH stat to where boiler is
Yes
then have another 3core/e between the two wiring centres
(what is this 3core for?)
LNE and switched live.

then all other wiring can be done at 2nd
fix

Yes if you can do it surface. If it's all in a dedicated area for example.

 

[Toneyz]

Are the boiler and HW cylinder both next to each other in the garage?

 

[123]

Just confirm with builder/plumber that it is a 3 core & earth to each UFH stat. Quite a few actually need a Cat 5 cable rather than a 3 Core & Earth.

 

[Judd]

Just finished a similar 1st fix myself but slightly different system,
Combi system and 6 zone UFH.
boiler and manifold in different rooms, took a 3 core to each stat wired back to the manifold, took a twin and a 3core from the boiler to the manifold, twin for the manifold feed and 3 core for a feed and switch wire back to the boiler, ( extra core just incase). If i were you i would have a pop at 2nd fix, read the manifold instructions and diagrams it pretty much tells you what to do.

 

[123]

I don't generally like the idea of putting an extra core in "just in case", but some plumbers/heating engineers/builders are clueless idiots and can't be trusted. I had plumber a couple of years ago asking for 3 Core & Earth and Cat 5 to be installed to each UFH stat as he hadn't decided what brand of UFH heating system he was going to install.

 

[Judd]

I don't generally like the idea of putting an extra core in "just in case", but some plumbers/heating engineers/builders are clueless idiots and can't be trusted. I had plumber a couple of years ago asking for 3 Core & Earth and Cat 5 to be installed to each UFH stat as he hadn't decided what brand of UFH heating system he was going to install.

I get where your coming from, but when you get that feeling from a customer ( the type that changes their mind alot) sometimes I'll take a 3-core to a light switch 'just incase' they want an extra light or a smart switch. Same principle, just thinking ahead.

 

[LankyWill]

I don't generally like the idea of putting an extra core in "just in case", but some plumbers/heating engineers/builders are clueless idiots and can't be trusted. I had plumber a couple of years ago asking for 3 Core & Earth and Cat 5 to be installed to each UFH stat as he hadn't decided what brand of UFH heating system he was going to install.

Some brands of UFH stats require sw live, live and neutral so you need a 3 core.

 

[123]

Some brands of UFH stats require sw live, live and neutral so you need a 3 core.

And some need a cat 5. You kinda need to know what you are working with before you can 1st fix

 

[bigspark17]

Where is the motorised valve for the ufh going next to manifold or next to the rest of them would be my guess by the boiler? If the later you could either run a 3c to the valve from the manifold and a twin for your 0v switch on for the boiler or just a 3c and can switch boiler on via motorised valvle local to boiler can be trickier if youve got the manifold on diferent supplies as youd have multiple supplies in the wiring centre but not a problem.
A conversation with the plumber about location of devices is essential, the good ones will often ask you where you want the valves.
Dont forget a 3c for the cylinder stat back to wiring centre.
So is this normal practice to sub out the heating wiring??
Respect for knowing your limits but im sure youve got enough about you to undertake this just need the confidence im sure..

 

[Leesparkykent]

I generally use heatmiser. If im going just programmable stats I'll use 230V thermostats and neo HW as I find it easier to fault find on. If the customer wants programmable thermostats and central screen control then I'll use heatmisers 12V version and run Cat 5.

 

[Toneyz]

That's the problem with plumbers it's like getting blood out of a stone as to what they are supplying (mains stats or L.V.)