Ariston Boiler cycling on and off with Hot water

[Adrian80]

Hi,

I'm not quite sure whats going with the boiler. Basically i can hear the fan and boiler firing up running for a minute then switching off, then firing up and switching off when running the hot water.

It doesnt seem to be a problem when using the shower as we get continuous hot water.

However, when filling the bath you really notice it going hot and cold all the time.

In my simple mind its like its overheating then switching off cooling down then coming back on again.

I would be grateful if you have any suggestions that i might try/test/replace.

I have one of these boilers

http://www.ariston.com/uk/Homeowner/media/files/560_COMBI A ISO - Inst, Serv _ User.pdf

I realise its a bit cheap and nasty but was in the house when we moved in.

many thanks.

A

 

[Adrian80]

Any ideass advice would be greatly appreciated.

 

[twgas]

Secondary heat exchanger probably getting blocked is most likely

 

[Adrian80]

Many thanks for the reply,

Can this be unblocked? i.e. a nice soak in a bucket of water with brick acid or is there some other magic cleansing that can be performed.?