Heatrae Sadia Premier Plus PP300B 300 Litre Unvented Indirect Cylinder The premier plus from Heatrae Sadia is an unvented hot water cylinder. The indirect model can only be heated by an external source. Heatrae Sadia guarantees the PremierPlus against faulty manufacture or materials for a period of 2 years from the date of purchase including parts and labour. This 2-year guarantee is extended to 5 years for the cold water control valve and expansion vessel, and to 30 years for the stainless steel inner vessel.