Worcester 20/25 boiler transformer

[Endaf4]

Hi hope you can help me

I've got a Worcester 20/25 oil boiler had a problem with the transformer, got a new one

When I took the control box off and the box where the wires get connected too, the brown wire for the transformer came loose, so I presume that might have been the problem, but I didn't see where it connected too

In the picture I've connected it to where I think it was, fan runs but ignition doesn't spark and goes to lockout

After looking everywhere online I can't find out where the brown wire goes, any help would be much appreciated

 

[oilhead]

The transformer is connected to terminal 3 of the wiring base. From you picture, something has scorched the earth wire which needs investigating.
The transformer can be tested by taking the live connection direct to the mains feed. Switch off all power to the boiler, connect the transformer then switch on the ower without the control box fitted. The electrodes will spark if all is well.

 

[Endaf4]

I didn't notice the scotch mark until I took the photo

I've finally managed to get a plumber to answer their phone, hopefully coming out tomorrow, and yes I did tell him what I did! Didn't go down well

 

[oilhead]

That is the telephone response to the tooth sucking intake of breath that you would have got face to face.

 

[Endaf4]

Great plumber just cancelled

 

[Endaf4]

The transformer is connected to terminal 3 of the wiring base. From you picture, something has scorched the earth wire which needs investigating.
The transformer can be tested by taking the live connection direct to the mains feed. Switch off all power to the boiler, connect the transformer then switch on the ower without the control box fitted. The electrodes will spark if all is well.

So the brown wire should be on terminal 3?

 

[oilhead]

Follow the wiring diagram in the manufacturers instructions. You may have a post purge unit fitted to your burner, Worcesters often did, which slightly alters the position of connections, although IIRC, it does not affect the transformer. There is another diagram on the base of the control box.
Have you tested the transformer as I suggested above?

 

[Endaf4]

All done, thanks