melted air pressure switch

[pipefitter]

Hi all,anyone had this problem before,gone to a call out with a worcester 28i not working,had a look inside & dicovered the air pressure switch nozzles had melted & closed themselves up put a new one on boiler fired & run within an hour the new switch had done the same ,switched boiler off decided to tackle it tomorrow morning when feeling fresh.any ideas

 

[Billy Bob Bob]

ah the 28i melted switch and t piece? its the pcbs fault it failed sent the wrong signal to the ntc and the boilers cooked the switch had it 3 times you will need a new pcb,new t piece and new ap switch,i assume you have checked gas pressures as well?

 

[pipefitter]

thanks for the quick reply ,yeah it melted the switch & t piece,not checked pressures yet as its unoccupied so i just isolated gas & power & went home,it was a bit late to get too involved i'm back their in the morning

 

[Billy Bob Bob]

well if its any conciliation all 3 i have repaired have had no repeats just check the pressures to make sure its not a gas valve issue but its unlikely my fix works good luck mate

 

[pipefitter]

thanks ,i'll let you know how i get on tomorrow

 

[boabgti]

had the same problem a couple of weeks ago replaced and no problem since

 

[Billy Bob Bob]

seems to be a common problem on this boiler affects 24i and 28i

 

[gasmarc]

bang on Gas Man ,I had this problem only once and took 3 visits to fix and yes i replaced APS and then the PCB and lastly the plastic tee piece was also distorted

 

[pipefitter]

cheers gas man changed pcb & problem is solved.

 

[Billy Bob Bob]

cheers gas man changed pcb & problem is solved.

glad to hear it pipefitter,thats the best part of this forum we can all learn from each other

 

[Propertyguy]

I had the same problem of a 28i Junior failing to light, melted air pressure switch and tee piece. Worcester informed me it is due to the fan not working at full speed. This can be caused by the fan itself or the pcb. With the fan running check the voltage at the fan. If it's 230v to 240v then it's probably the fan at fault. Outside this range it's probably the pcb. I checked mine and it was 240v. I replaced the fan, pressure switch and tee piece. Fired up 1st time, boiler now working. Cheers guys. V helpful thread.