Worcester Bosch 350 combi

[Dannypipe]

Hi guys, looked at a boiler last night. quite funny, I stopped in my local curry house for a take away and noticed everyone was wearing their coats.

Anyway, went into the kitchen which was chaos, and looked at their pig of a boiler.

The DHW side has been capped off and next to it they have fitted a water heater. It's covered in cooking fat, and the cover is held on with blue tac.

I had a quick look and found that there was a link in the room stat terminal on the PCB, and it just runs on constant.

There was no light in the demand diode on the front panel.

As for the firing sequence, there is no power at the fan. You can hear the relays click on the pcb, but no power is going up to the fan.

My impression therefore is it needs a new PCB ignition sequence board.

However on my trusty laptop of manuals, I couldn't find a manual for it with a fault finding chart, just a users document.

If this problem rings any bells with another engineer, let me know.

I was in a bit of a rush to get out the kitchen but as I like a curry from there reguarly I'd like to get the thing fixed for them.

Cheers,

Dan

 

[Dannypipe]

Oh and if anyone has a link to the installation/servicing manual I'd apreciate it. WB website just has users guide!

 

[Dannypipe]

Bumping this thread I hope. HELP!

 

[GrahamM]

Don't have the manual for the WB, but I just ordered PCB for an old Ideal where I having similar issue. Power supply OK. AP switch OK. Good resistance through fan. And all looks OK apart from fan getting no power from board.

 

[Dannypipe]

Cheers Graham. I've actually just found a link to the manual, via this site which is funny really.

Its at: HHIC » Worceter Bosch Discontinued Boiler Manuals

Looks like we have much the same problem. I just don't want to change the board, and find something else is also up to spout. Eventually you get to the point when people think your taking the pee, when all you're doing is repairing a pig old discontinued boiler.

Thanks for the reply. Good luck with yours.

 

[washer]

I think the 350 has a couple of pcb's, good luck, chuck a new one in!

 

[Dannypipe]

Yeah washer, it does have two boards, I've just looked through the fault finding doc and it's given me some figures to test for on the board. When I was at the resteraunt, all I could do was check for power at the fan, and power on the boards. They both have fuses, and I obviously checked them too.

I'd hate to put a couple of hundred quids worth of board in it, and it not work....not only embarrasing but also they need it fixed asap as there customers can't all sit around in their coats!

I'd like to just do a new install, as the boiler is in a right old state...but if I can repair it, and make it safe, then I will.

 

[tamz]

Check the heating pump (the one on the left) is working. This needs to start first.

 

[Billy Bob Bob]

grease has knackered one or both pcbs,you need to test further or speak to wb,i take it you have checked the high limit stat has not tripped? if the 350 has one

 

[Dannypipe]

Yeah, I found the high limit stat. Didn't find a problem there. The pump seemed to be running, hard to say as there was so much noise in the kitchen and there was no way I could have undone the bleed screw and checked it was turning....as it was a saturday night and the kitchen was in full swing...

My gut feeling is the boards are knackered...as you say grease, and steam will kill the boards off. I spotted a couple of resistors that looked like they had overheated, (slight black) but I could still get continuety across them. At the time, I had no numbers to go on, (resistance values in ohms)

The manual I have finally tracked down is going to help me...felt a right novice poking around in there and finally shrugging my shoulders and saying sorry can't help.

 

[Dannypipe]

I did mention that there was never any light in the 'demand' diode on the front panel right?

 

[Billy Bob Bob]

diode may have failed a long time ago

 

[Dannypipe]

Yeah...true. Thanks for the advice all.

I will have another crack at it on tommorow/tuesday. If I can rememember I will report back with the results....I actually need to do that with another thread I started! Will do so now!

Danny

 

[tamz]

Dan
Check your emails.

 

[Dannypipe]

Cheers Tamz, I don't know where you guys dig all this info up from but I love it!!