Bosch Worcester 280 Shuts off after 20 secs

[Ewm]

My Bosch Worcester 280 shuts off the boiler after 20 secs of running the Hot Water tap. The CH shuts off after about a minute or so.

This just started this morning.

As I watch it after turning on the HW, the pilot flame ignites then the main burner, then 20 seconds later they both shut off.

Very occasionally this year the Overheat has tripped but I don't think that's relevant, however!!!

Does anyone have any ideas

Ewm

 

[Agile]

It sounds like a boiler which has not been serviced lately?

There are several possibilities but the most likely is the fan/APS is not operating correctly. This would need a competent CORGI to deal with it though!

Tony

 

[Ewm]

My Bosch Worcester 280 shuts off the boiler after 20 secs of running the Hot Water tap. The CH shuts off after about a minute or so.

This just started this morning.

As I watch it after turning on the HW, the pilot flame ignites then the main burner, then 20 seconds later they both shut off.

Very occasionally this year the Overheat has tripped but I don't think that's relevant, however!!!

Does anyone have any ideas

This fault got worse over a few days until it would not switch on at all.


Well Worcester wouldn't give me any info over the phone and just suggested getting their engineer at £178 callout + parts
I downloaded the circuit from the website and the faultfinding flowchart (which was useless).

The fault I finally found was the Central Heating sensor sticking at about 2 Kilohms which was just on the edge for telling the driver board it was at full temperature (it's about 10k cold on a good one I measured at room temp.

Hope this helps somebody else


Ewm