Pumped UVC vent pipe?

[JamesPa]

Im struggling with where (or whether) to put a UVC in my retrofit, because the  existing cylinder is in the 'middle' of the house (on the first floor) and there is no obvious route for the vent pipe.

 

One ASHP installer is suggesting that it is OK to pump the vent (pump being below the tundish) and thus take it out through the loft.  I had the impression that the protection methods had to be 'passive', although in fairness the regulations don't actually specify this.

 

I could see an argument that its OK provided that the pump is tested occasionally.  The most likely fault scenario which disables the pump is electricity failure - in which case the heating to the UVC is also cut off so it 'fails safe' anyway.

 

Has anyone come across a UVC with this protection method, or indeed any other method which does not involve a passive vent.