extending valve wiring

[ChrisR]

Scuse me Ben but you must know stuff I don't, here.
I thought you CAN use 6 core flex for heating systems etc, iirc as long as both ends are visible, which they usually would be.


What's so dangerous about C plan? I'm not old or mean enough to have ever installed it!

Honda we need to know what your boiler is.

 

[honda]

Ben, have no valves at the moment but as stated intend to fit one 2 port valve as per c plan. never mentioned fitting two. can't see why this should create all the drama you mention---------or am i missing something?

Chrisr, the boiler is an old,but still good,floor mounted stelrad ideal type E.
the system at the moment is a conventional pumped CH with gravity HW.
want to fit valve to control HW temp.

any answers on question regarding dips on programmer?

 

[bengasman]

What's so dangerous about C plan? I'm not old or mean enough to have ever installed it!

ME NEITHER, ME NEITHER!!!!!!

Nothing wrong with CORRECTLY fitted c-plan with 1 valve.
Thishere plan is to add a valve to a c-plan, which makes it an incorrectly constructed s-plan.
With new valve/both valves closed, you could well be pumping the flow directly into the tank, or nowhere at all.
Probably large lump of castiron that takes 3minutes to warm up. if that cuts out by overheat stat on no flow, you can get a lot of steam that needs to go somewhere.
Old lump, corrosion, pinholes……

Not aware of any problems with multicore provided it is heatresistant when needed, and the right size.
Not aware of any regs that state both ends must be visible, what does that relate to? In what way should they be visible?

 

[bengasman]

Forgot to ask, 6-core??
I can see 3-core, 4-core, and 5-core in a c-plan, where does the 6-core go?

 

[honda]

Ben, DON'T have a c plan as i've no valves at the mo' but will have when i get one fitted.

 

[bengasman]

Ah, I see, missed the bit about NO valves, blimey, that could do with an upgrade.

Why don't you make your life easy and your system better by making it y-plan in that case?


Stick a 3-port on the split in stead of a zone valve on the return, the rest is virtually identical. Difference is that you now have a fully pumped, fully controlled system.
If you then set the dhw to come on before the ch, overlap for a minute or so to keep the boiler going and then turn dhw off with ch only running, you should notice a vast improvement.
Remove the wheel-head in the room with the roomstat, preferably in the lounge; this eliminates the possibility of boiler running unnecessarily when lounge rad is accidentally closed, provides interlock as required by apd L, and removes the need for a separate bypass.

 

[simond]

The 6 core or 5 core does not have to be heat resistant or visible both ends.

It does have to be adequately protected against adverse influences such as hot pipes, size 9 boots, etc etc. just like any other electrical cable.

If making the cable substantially longer, then the resistance of the protective conductor comes into account but in most domestic situations this is unlikely to be an issue.

There are no regulations specifically ruling out the use of all flexible cables and providing other requirements are satisfied a Part P inspection cannot find against the use of flexible cable, contrary to the old wives tales we sometimes see here.

 

[ericmark]

I have the same project to do for my father.

The programmer has both a dip switch and in the corner a screw hole which puts the physical restraint on selecting central heating with out hot water on or off.

Once the valve is fitted I will require 5 cores between kitchen and airing cupboard plus earth. As far as I am concerned that's the hard bit crawling through loft etc.

I don't think there will be either enough room in valve or thermostat to join cables inside either so I intend to fit a junction box in the airing cupboard. The standard ten way JB would not really work as pump etc. is in the kitchen but I did wonder if there is a standard wiring for the five wires in airing cupboard as I want to make it so anyone else can work on it in the future?

With two extra cables going to the programmer plus existing all surface at the moment I was going to fit a deep box to allow room to join cables and sink into wall.

As to using flex 16th Edition does say:- 521-01-04 A flexible cable or flexible cord shall be used for fixed wiring only where the relevant provisions of the Regulations are met.
Since June sees 17th Edition this may change and I can't work out what "relevant provisions" refers to and would not really worry but there are regulations not as reported on previous post.

As to Part P I am lucky as my mother and father are disabled so free of charge I only have to submit the installation certificate although not quite sure yet what I will test most likely PSC and ELI at socket feeding boiler and insulation test results. But not sure how to go about Part L2 since council paying for kitchen re-furbish it needs to be correct. I am not registered under part P but I am a "Responseable Person" as defined under the electricity at work act so can sign the installation certificate. i.e. I have C&G 2391 and 16th Edition plus degree in electrical and electronic engineering.

I do see the manufacturer of the boiler shows fitting of valve and thermostat without connecting back to boiler but I think the cycling this would cause would be waist full and may cause overheating so have gone for "C" plan.

I have also noted not all motorized valves have the internal switching required.

I hope what I have found helps you and would hope you will tell me how your job goes so I will not make any mistakes that you make.

 

[simond]

Ericmark said:

As to using flex 16th Edition does say:- 521-01-04 A flexible cable or flexible cord shall be used for fixed wiring only where the relevant provisions of the Regulations are met.
Since June sees 17th Edition this may change and I can't work out what "relevant provisions" refers to and would not really worry but there are regulations not as reported on previous post.

SimonD wrote

There are no regulations specifically ruling out the use of all flexible cables and providing other requirements are satisfied a Part P inspection cannot find against the use of flexible cable,

I said there are no regulations specifically ruling out the use of flexible cables for this application. I didn't say there were no regulations regarding flexible cables, so my post was accurate. Thanks for nothing, and I mean nothing .

 

[honda]

ericmark, thanks for comments and info. am also putting junction box in airing cupboard but just to extend valve wiring as already have extended wiring on cyl stat. nigef has suggested i use 2x3 core(plus earths) and label them accordingly. as regards the valve i'm going to use the honeywell v4043h.

hopefully will post on here how i get on but not as regards mistakes as i won't be making any. lol.