Keston Combi Boiler out of order thermostat

Hi Folks,

I have bought and installed a Keston Combi boiler four years ago. I have not faced any mentionable issue up until now. However, last night as I turned on the boiler to take the shower, the water that came out was extremely hot. I am unable to understand the actual reason behind it. Besides, at times the Keston combi boiler fails to work properly. Has someone got any idea what is wrong with the boiler?

Looking for your valuable suggestions


Hi Tony,

An aging and out of order thermostat at times becomes non-functional or incorrect. Because of this reason, it will leads towards very hot water and occasionally absence of the Keston Combi boiler’s daily operation but it solely depends upon how the thermostat is acting out. Before fixing this issue, it is important to check that the boiler’s thermostat is working either properly or not. If a clock & mechanical, timer is set accurately and Keston boiler’s thermostat is motorized then, I would advise replacing it immediately.