PulsaCoil - no hot water!!?

I moved into a new apartment which has a PulsaCoil 2000 installed. The heater seem to work normal - I see a green light and hear water boiling noise.

The small grey vent tank has full hot water...

But when I open any hot water tap in bathroom or kitchen I only get cold water!

I tried getting the boiler to run for 8 hours and stop valves are kept open.

Any idea what is going wrong here?

Thanks