The suggested "loop" system uses 40mm poly pipe with a tee off with 25mm feeder line into the hot water service (HWS). By positioning the HWS near to the most frequently used taps (kitchen and basin), the draw off before the hot water arrives is minimal and better than having small pipes that result in low delivery rates on low pressure. A two tap, single post mixer is ideal for ideal for a gravity fed system and allows better regulation of flow and temperature.