Worcester 28i Junior - Faulting when no CH demand

[DIYJamie]

Hi,

I’ve searched previous threads with no luck and I’m having the following problem with a Worcester 28i Junior.

This problem started after the room controller was changed to have the heating on for a longer period whilst painting, but has continued now the controller has been back to the previous setting.

The system has the following symptoms:

• If no CH demand, then the boiler will show a fault (1 second flashing)
  • It will reset for a few seconds before the fault light begins flashing again
  • Will only reset and run if a CH demand is imposed from the room controller
• If CH demand, then boiler will reset on pushing button and start as normal
  • With boiler cold (e.g. in the morning), if CH demand then boiler will start as above once reset (as above).
    • If DHW demand then the boiler will fault and shutdown.
  • If boiler allowed to run for 2-3 minutes before opening hot tap
    • Then the boiler will not fault, and produce CH and DHW as normal.

I had a central heating engineer around to look (prior to noting the scenarios above) and he suggested it may be overheating – but I suspect this isn’t the case as the boiler will fault even when cold in the morning. Do you have any suggestions for likely causes?

Thanks in advance,

Jamie

 

[CBW]

It could be numerous faults. Is it the standard efficiency 28i junior or the greenstar?

 

[DIYJamie]

Hi CBW, it's not the Greenstar version. Thanks

 

[ianmcd]

Hi CBW, it's not the Greenstar version. Thanks

sonds like the pcb, these are notorious on those , definately not a DIY job, get a Worcester fixed price repair