According to Filtered water from Quooker some (all?) quooker taps can provide both softened and direct water. Does anyone know details? Just a matter of connecting both sources, or are there snags, gotchas etc? 

 

Even if it's _possible_, next question is should you do it? I'm tempted to just do softened since it's a fragile device and limescale kills

For our Quooker the ‘hot’ water comes from the Sunamp which is a softened supply and only provides the hot water.
 

The ‘cold’ is direct from the mains via a Combimate water conditioner and provides the cold water.
 

That conditioned cold supply is what gets heated for the boiling tap and cooled/fizzed for the cold/fizzy tap. 

No scale build up from either supply and we’re not drinking softened water.