DeDietrich C230 ECO-A 120 Installation, Operating And Service Manual page 22

5 Water-side connections
22
It is strongly recommended that a decoupling device is installed to
isolate the boiler during non working times and/or when the system or
boiler flow is unknown
When the boiler is connected to a refrigeration system, it must be
installed so the chilled medium is piped in parallel with the boiler with
appropriate valves to prevent the chilled medium from entering the
boiler.
The boiler piping system of a hot water boiler connected to heating
coils located in air handling units where they may be exposed to
refrigeration air circulation must be equipped with flow control valves
or other automatic means to prevent gravity circulation of the boiler
water during cooling operations.
C230 ECO-A