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

[Darkwood]

Right ... Just been nudged to set this up by Paul.M and sounds a good idea following recent threads I've done in the Arms..

Rules....No Offensive material... edit if required before posting as this is the public arena.
Anything to do with the trade or in and around it ...H&S pic's welcome.



I've posted this a few times and this is at a mates house following a kitchen refirb several yrs ago. mg_smile:

 

[brianmoooore]

I would have used a TP isolator as well, but would have fitted it on a PVC surface box, fitted with a 20mm gland for strain relief of the flex.
Is there something a bit dubious where the flex connects to the boiler PCB?

 

[Raptor0014]

It's normal to fit a 3 pole isolator next to the boiler if the switchfuse is remote from the boiler, this satisfies manufacturers and gas-safe requirements for a local isolator to the boiler.
Obviously it needs to be 3 pole in order to isolate live, neutral and switched live.

That’s the point, it isn’t. The grey T&E coming down the wall is direct from the CU.

 

[DPG]

Yeehaw Ride em home, cowboy.

Now this takes thinking outside the box to a whole new level of special kind of stupid.

That’s the point, it isn’t. The grey T&E coming down the wall is direct from the CU.

No FCU?

 

[Raptor0014]

No FCU?

Nope, straight into a 6a MCB.

 

[Raptor0014]

I would have used a TP isolator as well, but would have fitted it on a PVC surface box, fitted with a 20mm gland for strain relief of the flex.
Is there something a bit dubious where the flex connects to the boiler PCB?

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.

 

[brianmoooore]

Nope, straight into a 6a MCB.

See this often on extractor fans, even though the manufacturer's instructions specify a 3A fuse.

 

[brianmoooore]

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.

Shouldn't the wires be pushed into the holes on the left of the block?

 

[Raptor0014]

See this often on extractor fans, even though the manufacturer's instructions specify a 3A fuse.

Funny you should say that….

 

[Raptor0014]

Shouldn't the wires be pushed into the holes on the left of the block?

No that's the screw terminals access.

 

[brianmoooore]

No that's the screw terminals access.

Ah! Thought it looked like maintenance free type push in terminals, and they'd jammed the wires down where you push a small screwdriver to release a wire.

 

[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.