boiler problems ariston euro combi

[maxmark]

helllo i've been having problems with my boiler ariston eurocombi sx 20 mffice it fires up fine when running hot water then when it starts to get hot it switches off and fires up again about 40 secs and repeats,same with the heating could you help.. mark

 

[ChrisR]

Heat dissipation problem. Could be pump running slow, though SLUDGE is more likely.

 

[AnonymousImport]

Most likely to be a thermostat or modureg problem. If you have this instructions use the fault finding guide.

Hope this is of use

 

[COG]

As chris said, had the same happen before pump running just abit too slow ,cleand pump and all ok but sludge could give the same prob either way a circulation problem. is it ok on a slow water flow rate ?