An expansion vessel and check valve kit designed for use with Hyco Speedflow unvented water heaters. This kit includes a 2-litre expansion vessel set at 3.5 bar and a one-way check valve. The expansion vessel weighs 1.0 kg and has a height of 225 mm, while the check valve weighs 0.1 kg and has a length of 65 mm. The product is WRAS Approved. It is suitable for the 5, 10 and 15 Litre Hyco Water Heater and comes complete with a 2 Litre Potable Expansion Vessel and a Floguard 15 mm dezincification resistant brass single check valve.