ferroli f30 - hw works but not ch

[candice]

The boiler's only 4 years old but the ch has stopped working twice (hw fine) - this was due to the clock timer being faulty although it still showed the correct time. Also, the last repair man replaced a 2 amp fuse as well as the clock timer. I don't understand why the timer should stop the ch altogether (and not the hw) - and where does the 2 amp fuse fit in?
I need to get to grips with it all so would greatly appreciate anybody's help.

[AdamsHeating]

hiya, the reasons the timeclock only affects the CH is that with combi's it's the tap that you turn on that activates the direct hot water (D.H.W). If you had a cylinder and all that jazz, then the hot water would be controlled by the time clock.

I've had a look in the manual for the F30 regarding the problem and this is what it says,

"If the boiler works for D.H.W. but not for heating the fault is most likely to be external controls (i.e. clocks or room thermostats), Integral clock if fitted or C.H. sensor. If the heating demand light is on the fault is most likely the C.H. sensor. If this light is not on suspect either a clock or room thermostat not calling. To override/eliminate any external controls disconnect them from terminal 3 and 4 underneath the boiler and refit the link wire (see fig. 36)"

Is the heating demand light on when the Roomstat is calling for heat? If so it is the CH sensor that will need replacing, if not it's a problem with the clock/roomstat.

AH.