Worcester 20/25 blowing internal fuse

[David G]

The motor live and neutral seems to be wired to the PCB connector X12 via the blue bundle. It doesn't look like it is dependent on a feed from the burner control box (TF830), though it's neutral wire is connected to one of the TF830 pins. That is why I tried it without the TF830 connected, and it still blew a fuse. This is what made me conclude it was nothing to do with the TF830, and must therefore be the PCB that was faulty. I have edited my previous post to clarify that I was talking about the burner control box, not the PCB behind the control panel.

I have looked at extracting the PCB - it doesn't look damaged as far as I can tell in-situ - but it looks like a real bugger to get out due to the thermostat pipes, etc. I am therefore heading towards getting it sorted by Worcester-Bosch under their all-in price repair. I tried, but I think I may have reached my limit at doing it myself

 

[oilhead]

The feed from the PCB feeds the TF830 which switches the motor.. You are probably wise to call in W.B . I would have thought that the only thing you need to access the PCB for is to replace the fuse. Favourite for the original fault for me would be the transformer, but with the correct fuse in the main spur, this is what usually blows. If the wrong fuse is fitted at the main supply, it often takes out other components.

 

[David G]

The man from WB came, and eventually replaced the PCB and got it working. It was gratifying that we (myself and you) had diagnosed the right problem. He also replaced almost everything else so we have now got a mostly new boiler

On the down side, he left us with a notice, and a sticker on the boiler, saying that we should have a guard on the flue (the old one having rusted away), that we didn't have adequate ventilation and that the oil tank should be 1.8m away from the flue

Our system was fitted in 1998, and as I understand it, the 1.8m rule only applies to tanks fitted after 2002. I can see that we should replace the flue guard, though we have no young children to worry about doing something stupid. I am not sure about the ventilation. We have a vent in the adjacent shower room, and I don't know if this is either the right size, is acceptable being behind a potentially closed door, or generally what the regulations were in 1998. Any advice would be gratefully received.

David

 

[Burnerman]

I'm sure today's installations are miles away from where they used to be David - so your system is probably like mine, not to current standards. Anyway, the boiler man was completely correct in pointing out those issues to you.....he's covering his own back at the same time.
Obviously the boiler, as it seems to draw its combustion air from within the room that it is installed in, needs a supply of air that it burns. Balanced flue systems draw their air from outside, so that's a different set up. Therefore, air vents close to the boiler are recommended, but the trade off naturally enough is a gale blowing in there which is not what you want either.
I do use carbon monoxide alarms in any room with a flued heating appliance though.
My own system gets enough air from underneath the back door and its not in an enclosed space anyway so I'm happy with that.
A flue guard is probably a good idea if anyone could conceivably get burnt by passing by the thing.
My own oil tank is too close to the building for current standards but I'm not shifting that!
Strictly my own opinion and I'm probably sticking my neck out but I'd leave things be.
Pleased your boiler is sorted!
John

 

[David G]

I have a bit of a worry that WB might not repair my boiler again, if I haven't rectified the things on the notice. Though, as I said, I am pretty certain the position of the oil tank isn't an issue.

David

 

[Burnerman]

In a similar situation I'd have a gaze of wide eyed innocence and say 'I know nothing'.......as per Manuel from Fawlty Towers
Seriously, worry ye not about that one.
John