Problems With Ferroli Domi Compact F30 B Heating and Water?

Hi,

I have the above boiler which is around 4 years old. Recently it has started giving me a number of problems and unsure if they are all related.

I now have these problems:

1. Despite the heating regulating dial being on very low the water is scalding out of the tap. However on occassions the shower runs cold when starting up and needs to be turned off and on in order to get the hot water to come through. I have read on the net that this could be because of a reduction in the hot water flow, although I have not touched the flow valve etc.

2. The bolider heats up to over 90 and then shows the letter E before cooling down.

3. After the Hot Water problem 2 of my rads were not heating up and I therefore tried balancing them. As a result some of the rads are warm with a number pretty hot.

Any advice appreciated.

Thanks

Joe