I AM HAVING A NEW COMBI BOILER FITTED SOON 'IDEAL isar HA24' AND HAVE BEEN TOLD THAT THE SHOWER ALREADY IN USE WILL NOT BE OF USE, AFTER THE NEW COMBI HAS BEEN INSTALLED. I UNDERSTAND WHY, AS IT WAS EXPLAINED TO ME - WATER TANKS AND PUMPS ETC. WHAT I WOULD LIKE TO KNOW NOW IS, WHAT KIND OF...