Keston C55 help needed!

[mrdudsir]

Hi folks,
I have a C55 which fires up on demand, running through all the start up codes, starts to heat for about 10 or 15 seconds then stops, showing code 6 - boiler is up to temperature - which it definitely isn't!. It waits a short while then tries again, never quite getting higher than 29/30 degrees. I thought it might be a dodgy room stat so replaced that but no joy.
It shows no error codes so I'm at a loss...
Any help is greatly appreciated...I'm FREEZING!

 

[seco services]

Is the pump running ?

 

[Agile]

I would expect the pump is not running! Or the boiler sensor is giving false readings.

There is little logic in replacing the room stat if the pump is at fault although I suppose its cheaper!

 

[mrdudsir]

The pump is fine, good even. The tepid heat it produces is traveling away and back with no problem. It's as if a temperature sensor is faulty, but I can't see one anywhere!