Ideal boiler DHW problem

[ArmiShanks]

Hello,
I hope some of you helpful people here could shed some light my boiler problem...

We have an ideal mini c24 combi boiler just recently it seems to be taking around 60 seconds to start supplying hot water from any of the taps. To start with the hot water is at a perfect temperature, however after a few seconds it begins to fluctuate between hot to luke warm to cold. The bath tap is significantly worse than the sink taps and I've resorted to topping up hot water in the bath off the basin tap. However all aspects of the ch as far as I'm aware are working perfectly.

The system pressure is between 1-1.5 bar
System temp is around 45c without the ch switched off; I read elsewhere this should be around 60c?

I've been through the installation & servicing manual found here

On page 42 & 46 it describes how to remove & test the diverter valve actuator. I've tested pins 1/2 & 2/3 with a multimeter with the spindle in both positions they read 9.35ohms.

What else could be causing the DHW temp to fluctuate? Are there other tests I could carry out that might help diagnose the problem?

Many thanks.

 

[gas4you]

Blocked/scaled up plate HE.

Incorrect burner pressures. Incorrect working pressure at the meter.

 

[davebgas]

run the DHW and feel the flow on the CH side, if it gets red hot the diverter is passing the heated water down to CH side. you tests would show on the actuator that its working ok by moving but the guts could be shot....