10
Alpha SolarSmart 100 - General Information
3.5 DRAIN BACK UNIT (DBU) INFORMATION - Fig. 5
Positioning
The DBU must be located below the solar collector bottom edge by no more than 4 m vertically to enable the pump to
circulate the water around the collector. The pipework from the collector to the DBU
must
fall continuously by a minimum of
40 mm per metre to allow the water to drain back into the DBU.
The pipework
must be
insulated with high temperature insulation.
Dimensions
The dimensions of the DBU and clearances required for servicing are shown in Fig. 5.
Fig. 5
DBU Connections
A
Return from collector to DBU 22 mm
B
Flow from DBU to collector
15 mm
C
Flow from cylinder to DBU
15 mm
D
Return to cylinder from DBU 15 mm
A
B
C
D
110
150
140
110
150
140
10
10
573
125
20
245
450
100
100
Water connections
The connections at the top and bottom of the DBU are shown in Fig. 5.
Note:
Use copper pipe and compression fittings only on the pipework between the DBU and solar collector.
