Space saver SS9 flow

[J444ES]

Hi,
I have just removed a double 100x70 rad from my kitchen and replaced it with a space saver SS9 which runs from the central heating. The boiler is a large combo oil condensing boiler and comfortably heats all the radiators so much so I usually only run it on 4.
The space saver has a fan in it that turns on when water temp is over 38deg this happens but as the fan cools the water in the heater it drops below 38 deg and turns off its like the flow through the heater is not fast enough the supply pipes are 10mm micro bore. Has anyone else had similar problems? Anyone think of a solution or have experience of space savers (I'm not replacing the micro bore with 15mm) ? Oh n I checked the pump it's on max!
Cheers James

 

[Madrab]

Have you balanced the system? If it's losing heat too quickly, the system may need to be optimised. I assume it's been bled?

 

[J444ES]

Yes they were all bled but no I didn't balance them kinda figured one out one in - no need, but there was as now it's working just perfectly!
Thank you