Ariston Micro Genus MFFI 23 - Cold shower

Hi,

I have a problem with the flow of hot water from my combi boiler. If I turn any hot tap on I get hot water come through quickly but it then turns cold, if I turn the tap off a little (reduce the flow) the boiler catches up and hot water comes through again. It seems to not be able to supply the water quick enough - or maybe passes over the flame too quickly.

This means a shower is out of the questions and I can only run a bath quite slowly - even then it does not run a full hot bath.

I have tried descaling the heat plate - it wasn't that dirty and has made no difference.

Would anyone have any advice they could offer me?

Thank you for reading

It's a bit of a weedy combi so you shouldn't run a hot tap more than about 8 litres/minute if you want bath-hot water.
Winter mains water somes in colder than SUmmer, and you'll have noticed the difference.
If you run the tap at about that rate, about 4 of the temp lights (I can't remember what they represent) should come on, the boiler burner should NOT go on and off, and one revolution of the red arrowed dial (1 cubic foot)on an imperial gas meter should take about 42 seconds.