Hi,i have a Keston C40 about 4 years old.I have no error codes.The boiler starts at normal code 1 then through 2 and 4 for about 1 to 2 mins,it then runs through code 8, 0 and 5 very quickly and returns to 1 and the sequence starts again.Any ideas?.

John M, April 2010

Have been to a somewhat similar problem with a Keston today. Cannot remember if the codes were exactly the same as the ones you describe, but definately similar. I deduced that the unit was shutting down as a result of the DHW set point been achieved. It looks as though the DHW potentiometer is defective as it cannot be adjusted above 30 degrees.

Dumb Plumber, April 2010

It sounds like you have a faulty or incorrectly adjusted component that is not letting the boiler complete its ignition sequence.

Save yourself a lot of grief and get an engineer to look at it. If you haven't had the appliance serviced in the last 12 months, this may be a good time to do that as well. Many ignition faults are down to poor servicing.

This repair should be carried out by a Gas Safe Registered engineer who has HEATING registered on the rear of his ID card AND has experience with sealed systems. If his ID card is in the name of a company, he is only allowed to carry out this type of work when working in the pay of that company. NOT doing a cash job.

TheHeatingMan, April 2010