non-return/solenoid option can be fitted to prevent back siphoning of fluid
into the chiller during maintenance.
They are recommended when the chiller and application are at
different levels (more than 2 metres height difference), or where a long length
of flexible tubing is used between the chiller and the application. It is also
advisable to add non-return/solenoid valves in situations where pipe-runs will
be going up into ceiling ducts.