Maximum Water Loop Volume (Evaporator And Condenser Side); Expansion Tank; Protection Against Cavitation (Option 116) - Danfoss BW10 020-090 Installation, Operation And Maintenance Instructions

It may be necessary to add a buffer water tank to the circuit in order to achieve the required volume. The tank must itself be
internally baffled in order to ensure proper mixing of the liquid (water or brine). Refer to the examples below.
5.9 - Maximum water loop volume (evaporator and
condenser side)
Units with hydronic module incorporate an expansion tank
sized for the maximum water loop volume.
The table below gives the maximum water loop volume (in
litres) for pure water or ethylene glycol with various con-
centrations.
BW10 020-045
Static pressure kPa 100
bar 1
Pure water l 220
10% ethylene glycol l 165
20% ethylene glycol l 100
35% ethylene glycol l 85

5.10 - Expansion tank

The expansion tank is supplied with a pressure of 1 bar relative
(±20%). The maximum operating pressure for the tank is 3 bar.
20
Bad
Bad
060-090
200 300 100 200
2 3 1 2
450 75 340 225
110 53 255 170
70 35 150 100
55 30 130 85
Good
Good

5.11 - Protection against cavitation (option 116)

To ensure the durability of the pumps in the integrated hydronic
modules, the control algorithm of the BW10 units incorporates
anti-cavitation protection.
It is therefore necessary to ensure a minimum pump entering
pressure of 60 kPa (0.6 bar) during operation and at shut-down.
A pressure below 60 kPa will prohibit unit start-up or cause an
alarm with the unit shutting down.
In order to obtain sufficient pressure, it is recommended:
300
3
• to pressurise the hydronic circuit between 100 kPa and
115
300 kPa (1 and 3 bar) maximum on the suction side of the
85
pump,
50
• to clean the hydronic circuit before charging water,
45
• to regularly clean the screen filter.