combi boiler hot water problem

[step]

hello
I have an old worcester combiboiler. it works fine for the heating, but not for the hot water. it takes a long time to get the hot water in the shower (which is a floor up the boiler) and after 30 seconds or so of hot water it switches off and the water is cold for about 30 seconds as well and hot again and cold...I live in a very hard water area. I wonder if it could the problem and what could the solution.

thanks!

 

[gas4you]

Domestic side of boiler sounds scaled up causing it to overheat and cut out.

 

[step]

hi thanks for your answer.
question: what is the domestic side?
thanks bye

 

[jj4091]

Hot water side, most combi boilers have separate hot water & central heating distribution.