Rinnai continuous-flow water heater also serves underfloor heating
The first installation in the UK of a Rinnai KBM continuous-flow water heater also serves underfloor heating. Dave Winrow, who runs Winrow Building Services, was asked by Rinnai to trial this low-NOx water heater. It has been installed into a retail complex that was being refurbished. This former Co-operative building houses a hair salon, separate beauty salon and one other unit.
The KBM currently provides hot water for one shower, two hair-wash stations and three sinks — including two in the clinical rooms of the beauty salon for podiatry and piercing.
Dave Winrow explains how the system works. ‘The system is on secondary return, so the water flows through the shop to the basins and shower. It is then mixed down to around 43°C. On its return, it flows over a plate heat exchanger to a manifold where the temperature is controlled by a pump and a motorised valve.
‘We only need 27°C for the underfloor heating, so that’s plenty going through the plate. It is then separated — clean water for the salons and the rest for heating. I have also installed two separate expansion vessels.’
The KBM unit has enough capacity to serve a couple of hot taps and underfloor heating when the other unit is occupied.
There are more units upstairs, and their requirements will be met by bolting on another KBM unit.