Navien NCB300 28kW Gas Combi Boiler – Stainless Steel Heat Exchanger ErP A/A+ LPG Conversion Kit Included This compact 28kw gas combination boiler features a stainless steel heat exchanger, 26kW central heating output, 37 kw domestic hot water peak. As standard, the boiler has an ErP a efficiency of 93%, increasing to an erp a+ efficiency of 98% when using the optional Navien smart plus controls. This results in a 7:1 modulation ratio. An LPG conversion kit is provided as part of this package. The flue can extend up to 8m. The Navien NCB300 is hydrogend blend ready to 20%. It is rated ipx4. The emissions class of this product is NOx class 6. Dimensions are 680 x 395 x 285 mm. Its net weight is 29 kg and has a lifting weight of 30 kg. There is a 5 year parts and labour warranty offered with this product (subject to terms and conditions - registration at