Franke Minerva 3 in 1 hot water tap plumbing advice

[Jules]

Our newly installed franke hot water tap keeps running out of hot water when there is plenty in our heating system. Is this because the hot water supply is also coming from the small Franke boiler? I had assumed it would be just the boiling water part of the tap that this tank feed and the hot and cold water would still come from the usual old supply. Do you have a choice when plumbing in the tap where the hot water supply is from ? if so is it simply to swap so we don't keep running out of hot water when we have loads available in our old hot water tank upstairs. thanks

 

[rpm]

https://www.franke.com/content/dam/corporate/gb/en/ks/pdfs/IBW_maintenance_table1.pdf?force-download=true

 

[Pierre]

When fitting the franke Minerva 3 in 1 hot tap do the normal hot and cold supplies go straight to the tap and not through the M Box.