Biasi 24s dhw problem

[timber66]

Hi
I have a eight year old biasi 24s heating works fine the problem is the
dhw, the temp of the water go hot then cold ,hot then cold agian the boiler
turns on for about 20 seconds then turns off then back on agian and so on.
The temp gauge reads about 85.
Any ideas thanks.

 

[Agile]

Thats a classic symptom of a blocked plate heat exchanger.

It needs to be cleaned or replaced.

When its clean the temperature should not exceed about 60°C on the gauge during DHW usage.

Tony

 

[timber66]

Cleaned out heat exchanger, now working fine.
Thanks for your help.