Baxi solo 2 pf 40 Wiring confusing me

[jonestom]

There is a 5 core cable on the boiler from left to right as I look at the boiler there is
L Black wire
N No wire fitted
E Normal colour earth wire fitted
E No wire fitted
N Blue wire
L Brown wire
SL Thinner black wire
What does the first black wire do? No matter what heat is called for either CH or water only, there is no power to that black cable.
I've followed it to the distribution board and it goes to number 10 linking up with the Brown wire from the pump, nothing else goes to number 10 other than those two wires.
Can anyone advise on wiring this boiler up using the Y plan system fully pumped with mid position valve V40734 fitted. all the wiring diagrams I have show the boiler with only 3 wires L N E I want ensure everything is right according to Diagrams, then I can try and sort my heating out,
Regards
TC

 

[gas4you]

Black wire is supply live to the pump. The boiler controls the pump live and consequently the pump over run.

Should be live when boiler is firing.

 

[seco services]

L pump live
n pump neutral
e pump earth
e earth
n neutral
L Perm live
SL switch live

 

[D_Hailsham]

There is a 5 core cable on the boiler from left to right as I look at the boiler there is
L Black wire
N No wire fitted
E Normal colour earth wire fitted
E No wire fitted
N Blue wire
L Brown wire
SL Thinner black wire
What does the first black wire do? No matter what heat is called for either CH or water only, there is no power to that black cable.
I've followed it to the distribution board and it goes to number 10 linking up with the Brown wire from the pump, nothing else goes to number 10 other than those two wires.
Can anyone advise on wiring this boiler up using the Y plan system fully pumped with mid position valve V40734 fitted. all the wiring diagrams I have show the boiler with only 3 wires L N E I want ensure everything is right according to Diagrams, then I can try and sort my heating out,

Using your wire order:
L black Pump live, which it is as it connects to the brown lead of the pump.
N no wire fitted Pump Neutral. The pump will be be connected to a neutral somewhere else.
E Normal colour earth wire fitted Earth connection (usually for pump) but the pump may be earthed elsewhere.
E No wire fitted Also an earth connection
N Blue wire Neutral Connection
L Brown wire Live Connection
SL Thinner black wire Switched live from CH thermostat

Does the pump work when the boiler comes on? It should do and the black wire should have 230v on it.

As for wiring a Y plan, there are two things that matter:

1. Ignore any pump connections on the Y-plan wiring diagram; the pump is connected directly to the boiler.
2. There must be a permanent supply to the boiler.

So in the diagram below:

1. Boiler L terminal should connect to terminal 1 not terminal 8
2. There should be no pump live connection to terminal 8
3. The SL terminal of the boiler should connect to terminal 8

All other connections as in the diagram

 

[jonestom]

Thanks for the reply everyone, the black cable connected to L on the boiler is never live.
The Brown Live cable from the pump and the Black cable that is never live both go into Number 10, nothing else connects to no/10

(just to confirm for D Hailsham)the Brown 'live' wire from the boiler does go into no/1

When I ask for CH or HW or both I get power to the SL, but never get anything on the Black wire L on the boiler.

Therefore presumably if that black wire should be live, where does it get it's feed from? The controller?

This is probably why the pump keeps playing up despite it being new.

Anyone any ideas where to look other than what I've assumed ie the Controller
TC

 

[seco services]

is the boiler firing up ?
then is their voltage at the sl ?
then is their voltage at the black pump live ?

 

[jonestom]

The boiler fires up and I get live at the Brown Live and the Switched live, but I don't get any reading on the Black live at any time, shortly after firing up say acouple of minutes or so and the boiler kettles because the pump doesn't run, I know the pump is ok because I've tested it separately.
TC

 

[seco services]

check the fuse on the pcb.

 

[jonestom]

will do ist thing in morning, will report back tomorrow, thanks for your help and advice.
TC

 

[jonestom]

Yes, great advice from everyone, thanks to Seco services, the fuse had blown on the PCB.

I've learnt quite a lot about central heating and boilers, in the past couple of months, and it's thanks to this site.

Who knows I could be giving advice on the site myself one day.

Ill keep you all busy and recommend the site to all my Buddies.

Regards

TC

 

[seco services]

did it cure the problem and is it up and running ok

 

[jonestom]

Yes it did, the boiler fired up, the pump ran, I bled all the rads and the system has ran spot on since then.

I've stopped and started it several times via the programmer and it hasn't flickered, so I guess it's sorted.

Don't know why the fuse blew though. Maybe just 'tired' as one of my Elctrical workmates would say.

So thank you again, you've made my Easter a warm one.

Regards

TC

 

[gas4you]

I've found that often, but not always, the fuse on the board blowing could point to the pump.

 

[jonestom]

System still running, fingers crossed, we've cracked it, but I'll bear it in mind about the pump, as I have had several issues and they've all been pump related.

So that's top of my list if the pronlem occurs again.

Regards

TC