Ferrolli combi 77ff intermittent hot water

[Davitrons]

Hi, wonder if you can help a long time lurker but first time poster....

Had many problems with my aged boiler (can't afford to replace at the moment).

Main problem is with the hot water. It either:

refuses to fire the boiler up on demand of hot water (CH is fine), or
boiler starts up, then goes off and water will just run cold
boiler starts up, water gets hot (usually too hot), then boiler goes out for 2 mins, then boiler kicks in again, then off again whilst the hot water is running.

I'm not looking to do anything to the boiler myself, just wondered if anyone could give me any likely fault areas ?? I've had a scout around in the posts on here, but not really knowing anything about it there are so many things mentioned and I can't find a post that exactly matches my issue.

thanks in advance!

 

[Llan1observer]

flow switch...

you can trick it into giving warm water by running CH while running tap.

the 2 mins off is the anti cycling programme

 

[Davitrons]

thanks. We used to do the trick with the CH, but it's a bit too hot for that!

 

[DP]

Running CH will do nothing for HW on this boiler. Perhaps the poster might want to look at the boiler- it does not have a diverter valve. ALSO the pump does not operate for HW BUT it does for CH. The HW flow switch would be an item I would be looking at after checking the lights to see what the PCB is 'seeing'