Baxi 600 electrical connection

[niren]

Howdy - first post and need some advice. Baxi 630 boiler

To start with i am not qualified in anything and i know the wiring in the photo is from the 90s. Please bear with me....

We had a new boiler fitted a couple of weeks ago by a certified gas engineer. He was a sub of my builder. At the time my programmer was bust so the gas fitter couldn't test using the controls. I've now installed tado which all works fine but the boiler doesn't fire up for heat. I am no expert but was comfortable enough to test the connections at the programmer for being live when calling for heat I then tested the switch live in the boiler and a signal is being received (all done using a screwdriver tester - like I said no expert!!). The lights all lit up which to me means the boiler is receiving signal to switch on?. This is the wiring - not done by me but a subby employed by another subby of my builder - into the boiler from the fuse spur. Switch live is black.

Is this correct? FWIW the boiler is about 2 weeks old. When the gas guy fitted it he tested by plugging directly into a socket. Reason i ask is doesnt a switch live need a neutral to come back to complete the circuit? Sorry if i sound stoopid - just want to check before forking out....

I have also taken a screengrab of the installation manual that shows where the connections should go. Has this been installed corectly?

 

[buzzlightyear]

My advise is get a spark in to sort it out .other wise it could be a expensive mistake.just to elitarate why are you using a neon screw driver for testing you could have used your finger

 

[Bob Geldoff1234]

The red and blue wires aren't properly in their terminals for a start.
B1 and BK2 is a switch that turns heat on or off for the rads.Usually there is a link in these two terminals and the boiler will fire up.In the diagram it then shows a room stat as the switch.I cannot help you further as I don't know what your connecting to BK2 using the black wire but as a guess it could be needed to move over to B1.

 

[Octopus]

Get the installer back to finish the job properly....

 

[buzzlightyear]

BobG, it would be advisable not to give the op instructions how.

Or the gods will strick lighting up your a&&.

 

[niren]

Thanks for the advice chaps. Yes I’m pretty peeved at the whole job but partly have myself to blame. Bob the black wire goes through the fuse spur and connects to the call switch on the thermostat if that helps. Tado doesn’t need it

 

[telectrix]

The red and blue wires aren't properly in their terminals for a start.
B1 and BK2 is a switch that turns heat on or off for the rads.Usually there is a link in these two terminals and the boiler will fire up.In the diagram it then shows a room stat as the switch.I cannot help you further as I don't know what your connecting to BK2 using the black wire but as a guess it could be needed to move over to B1.

i think the black feeds 230V to the staat, but should there notbe a 230V return to terminal b1?

 

[PEG]

Hi,has your builder's subbies subby read note 9?

 

[niren]

No he has not - the instruction book was unopened! My thoughts were the same as ive ruled out pretty much everything else - i need to move the black cable to the connection above it.

I want to try it but am a little scared of something blowing up - but i will also be furious if i paid a pro a wad of cash to just do the same thing....ARRRGGHHHHHH!!!!

 

[Deleted member 26818]

Just from looking at the pictures, you appear to have no switched live from the thermostat to the boiler.
The wiring diagram shows 230V from the boiler (bK2) to the the thermostat which should then return to the boiler (b1).

I assume that a link between b1 and bK2 would eliminate the thermostat.

Main concern, is that there is only the one cable.
There should be two, one from the fused spur to the boiler feeding Line Neutral and Earth, and another cable between the boiler and the thermostat. Connecting b1 and bK2.

The diagram shows he thermostat having it’s Neutral fed from the fused spur, so it’s possible the fused spur also feeds the the thermostat Line?
In which case, the Black wire would have to be moved from bK2 to b1.
Really need to see pictures of the wiring at the fused spur.

 

[telectrix]

post #7.

 

[Deleted account]

I think Bob and spin have have got it, but get then installer back in case you blow the Pcb by wiring it wrong. The installer should have finished the job.

 

[niren]

Thanks again folks. The black wire passes straight through to the NO contact in the stat. There is a brown wire that goes from the programmer to the COM point in the stat which is live when heating is switched on. Tado switches on/off wirelessly. Does this additional info help? I note the black wire is connected via choc bloc in the fuse spur so doesn’t pass through any actual terminals. Also the neutral in the stat is not needed for Tado so is parked in a dummy/empty slot according to the instructions. This is connected to the neutral in the timer but doesnt actually do anything.

Does this help?

 

[niren]

Folks I’ve sketched out all the above if it can help. I’ve also attached a diagram showing the programmer box and the com from the stat is connected to terminal 4.

Tado switches to terminal 4 to be live wirelessly.

 

[Wilko]

Hi - I'd not be touching without a proper voltage probe to confirm it's safely off, all conductors at all points. An Electrician can sort this for you on site, or the Tado website has approved installers for £90 to do this job, just saying.
Has your new boiler completed it's Gas Safe installation? With no controls present I'm not sure.

 

[niren]

hi Wilko - yes the boiler was gas safe confirmed. At the time my timer was broken so couldn't be tested but the boiler was fired up by bypassing the controls as part of the initial checks.

The fuse spur is connected to the FCU so i can isolate from there. There is no power going to anything when i do.

 

[davesparks]

It looks like the live feed to the controls should come from bk2 and the switched live connect back to b1
Currently you appear to have the live feed to the controls directly from the sfcu, the manufacturers may deem this to affect the warranty as it has not been connected in accordance with their instructions.

Are you in the UK?

 

[niren]

hi Dave - yes i'm in the UK. The FCU connects to the fuse spur directly and the fuse spur then feeds the boiler and controls. Is this not correct?

 

[Deleted member 26818]

I would (after switching everything off) just move the black wire from bK2 to b1.
From reading the various wiring diagrams, that seems to be what is wrong.
The thermostat being fed direct from the FCU means the boiler cannot switch the live to the thermostat (which it may not need to do anyway).
It looks like the switched live is going to the box with COM and NO, and then should return to the boiler terminal b1. Instead it is returning to the live output bK2.

 

[niren]

Thanks Spin - Im going to check whether the black is switch live by connecting everything up and see if the connector receives a signal when the heating isn't being called