Just had my boiler checked and now the engineer has left the upper potentiometer when you turn it just says cOFF. The lower one is fine and the boiler runs fine. Won't chase the engineer as he obviously had no experience of Keston boilers.
speak to Keston on their technical helpline. The boiler has a nasty habit if turning one of the zones off when you power it off. Keston will talk you through which buttons to press as some are hidden. The instructions on how to do it are in the original instructions if you still have them - good luck :-)
Paul
September 2016
It sounds like the 2 or 3 port valve is stuck you need a replacement. Do you have an airing cupboard with a hot water cylinder or is it a combi system?
alan
September 2016
It runs fine on the hot water , nothing happens on the heating side. It's not a boiler fault as such, the guy fiddled with the hidden buttons
Rob
September 2016
If the boiler runs fine then leave it alone.
What makes you think you know better than the engineer.
September 2016
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.