Dodgy trade pictures for your amusement! - 1 Million Views!

[timhoward]

If you follow the black wire from the flex which is in terminal RT. That leads back to the centre common on the 3 pole switch.

The only cable connected on the outgoing 3C&E is the brown into Common L1

The L & N on the T&E are connected to L2 and Common N.

I might be mistaken as I’ve not seen a new boiler like this round my way. Most are old style S-Plan systems from oil boilers. But I’m not sure how that is ever going to supply the right signal from the controller.

If I had to guess, it looks like the black and red are the supply from the CU, and are joined to the blue and black on the boiler flex.
That seems wrong if the flex black is the switched live.
I'd assume the 3 core is the incoming switched live from a controller, and this appears to go to the brown in the boiler flex.

So boiler side, if black is the switched live, and brown is the PL it's definitely mixed up. I'm also intrigued where the controller is getting power from.
Any rate, it's prove everything from first principles and start again, with an FCU!

 

[Raptor0014]

So what I’m trying to fathom, as the instructions aren’t great. Is how this should be wired as the Vaillant engineer said it should be wired with a 5 core cable.

They have done that but cut some of the cores in the flex and only wired one to the controller.

This is how the instructions say the power should come in. Sorry not very clear as it’s a photo I took to take away and look at.

So L, N & E

If you then wire in a controller you have to do it like this. So the live is doubled up and switched live is in RT. The bridge has been removed as I checked it.

So it seems it’s a bodge between 3 & 5 core wiring. But I need to work out how to wire this now and plumb in a FCU as well.

 

[timhoward]

So it seems it’s a bodge between 3 & 5 core wiring. But I need to work out how to wire this now and plumb in a FCU as well.

It just needs a supply and an extra core for the RT terminal.
When the RT (room thermostat) terminal becomes live, the boiler will fire. The Live can come from the supply side, it doesn't need to loop back.
You also need to remove the little link that says "ignore the room thermostat" on the other plug as per your photo.

 

[Raptor0014]

It just needs a supply and an extra core for the RT terminal.
When the RT (room thermostat) terminal becomes live, the boiler will fire. The Live can come from the supply side, it doesn't need to loop back.
You also need to remove the little link that says "ignore the room thermostat" on the other plug as per your photo.

That link has been removed.

The 3C & E goes to the controller. So when I go back next week I'll have to look in that and see which core is connected to the RT in that.

At the moment if the CH & HW are left on it stays working. However, because the RT is obviously not connected, if left to be controlled on a schedule it then won't fire up and throws a fault.

Hence I think I might need to start from scratch, put a FCU in and then work from there.

 

[brianmoooore]

Until proven otherwise, you have the possibility of the system being fed from two supplies. You'll have to investigate where the supply for the controller comes from and make sure both supplies go through the same FCU/main isolator.

 

[LewisM]

BG Of course

 

[Dustydazzler]

Nothing screams builders board change more than a BG

 

[LewisM]

Nothing screams builders board change more than a BG

Close, it was the man who came to fix the flat roof that was leaking

 

[timhoward]

BG Of course

That's a cracker!
You can easily see that those two extended cpc's once had a former happier life when they lived in Wylex land....

 

[LewisM]

That's a cracker!
You can easily see that those two extended cpc's once had a former happier life when they lived in Wylex land....

Yup was a old wire rewireable fusebox.

Garage flat roof leaked into light and blew the fuse, man came out to fix the flat roof and said e could upgrade the board aswell and as you can see.......

 

[LewisM]

Also never let the customer measure the cable and say there is plenty to work with

 

[davesparks]

Wow, connector blocks are a rare sight these days, I can't remember the last time I used plastic ones!

 

[LewisM]

Wow, connector blocks are a rare sight these days, I can't remember the last time I used plastic ones!

Yeah I had 10mm butt crimps but no heatshrink

 

[westward10]

Connector blocks have holes in the middle of them for a reason.

 

[mainline]

Close, it was the man who came to fix the flat roof that was leaking

I wonder if he was the same man who did the roof to begin with.

 

[Dave OCD]

BG Of courseView attachment 105701View attachment 105702

Lovely work, both RCDs bypassed with the busbar also connected to the outgoing line and neutral on both. It takes a special way of thinking to produce work like that.

 

[mainline]

Lovely work, both RCDs bypassed with the busbar also connected to the outgoing line and neutral on both. It takes a special way of thinking to produce work like that.

Yes, but you must admit it sorted that tripping problem out.

 

[Dustydazzler]

Yes, but you must admit it sorted that tripping problem out.

Its certainly one way of doing it , its amazing the amount of different ways I come across that someone has used to bypass the RCD

 

[BenCos18]

Yes, but you must admit it sorted that tripping problem out.

Haha that's for sure lol
It always both amazes and annoys me how badly some people do the work tbh

 

[littlespark]

I wonder if he was the same man who did the roof to begin with.

No. That was the electrician.

Connector blocks have holes in the middle of them for a reason.

Easier to snap apart?

Never liked using them as a fixing hole, unless it’s a really thin screw.
The thread cutting into plastic could get too close to a live terminal.