Hi
My worcester bosch 28i combi boiler packed up(4 yrs old) so I took a look and found fuse 1 had blown. After a couple of blown fuses later I decided to look a bit deeper and found that the fan motor had burnt out.( don't know how ,maybe moisture/condensation) I did some checks and replaced the fan and fuse 1. The fan came on and power was back but I am unable to get the boiler to light.Press the reset and light flashes 4 times/sec which indicates just about anything may be wrong. I have carried out continuity checks and resistance checks as per the installation guide and it all seems to point to the pcb.
Does anyone have any ideas to suggest it may not be the pcb? I'm thinking logically that as the boiler was ok, maybe the fan shorted out and took out the pcb!
When I switch the heating on via the programmer the relay clicks and seems to have a bit of a flash not so sure this is right.
Thanks to anyone who may be able to help.

Steve, November 2008

not a prob ... glad your warm now matey !!!

matt, November 2008

Hi matt

I'm up and running again new fan and new pcb about £160 delivered I've done so many different checks on this thing I feel like it's part of me. Lets hope it lasts.
Thanks for all your input mate it was good of you to keep looking out for my replies.
kind regards

steve, November 2008

british gas do a one off repair parts and labour for around £190 i think , less if you get your gas or elec from them might be worth a phone call ?

matt, November 2008

Thanks Matt

I linked the wires temporarily as you suggested no luck.I know the pump and fan are running ok the air pressure switch seems to be ok and I have checked and double checked all the connector pins and switches all seem ok, I've even checked the resistance is not geater than 100ohms across the transformer pins.The boiler seems to do everything right up to ignition and then it fails to produce a spark so I 'm gonna get a pcb.. ouch!! I believe only the fan and pump can obliterate a board and these are working now so even if I've got this wrong hopefully the new board will stay in 1 piece. WB charge a flat £285 which includes parts and labour seems a bit steep but by the time I'm finished I may regret not getting them in!! I'm sadistically sort of enjoying this i'ts the engineer in me but don't tell the wife!!

steve, November 2008

i trust the boiler is a 28i junior ? flashing 4 x a sec could be a sensor error or pcb , it also can be the pressure switch , seeing that you have mucked around with that part/parts of the boiler i would suspect this is the area of the prob [ could be wrong !] if u link the pressure switch wires together [ power off first !!] does the boiler work ? I STRESS IF IT DOES THE WIRES CANT BE LEFT LIKE THIS , IT IS A TEST ONLY! the pressure switch is there for a reason ! good luck

matt, November 2008

Hi matt
I blew the pipes out and put them back the way they came off. I checked for continuity between the connector and the wires to the pressure switch. I removed the wires from the pressure switch turned the boiler on and checked for continuity between the 2 terminals while the fan was on these checks were all ok.

steve, November 2008

have you replaced all the rubber tubes from the fan to the pressure switch back correctly ? is the pressure switch making ??

matt, November 2008