System boiler + unvented cylinder

[LordFrederickIII]

We have a Viessmann Vitodens 100 system boiler connected to an OSO unvented cylinder.

On the boiler there are controls to set the hot water temperature. Similarly, the OSO has controls to set the hot water temperature as well.

Is the system boiler control redundant as it doesn't seem to affect the temperature on the OSO cylinder?

 

[muggles]

Yes, the boiler control is redundant

 

[Agile]

I was really wondering if your cylinder is set up properly as you seem to find it running out of water so often.

But without knowing the shower flow rates, duration and the hot water heat up times as set then its impossible to guess where the problem may lie.

Tony