Water Connections; Operating Precautions - Danfoss BW10 020-090 Installation, Operation And Maintenance Instructions

The calculation is based on PVC or XLPE insulated cables
with copper or aluminium core. A maximum ambient
temperature of 40°C has been taken into account. The given
wire length limits the voltage drop to < 5%.
IMPORTANT: Before connection of the main power cables (L1
- L2 - L3) on the terminal block, it is imperative to check the
correct order of the 3 phases before proceeding to the
connection on then terminal block or the main disconnect/
isolator switch.
6.4.2 - On-site control wiring
Selection of minimum and maximum wire sections for connection to BW10 units
BW10 Max. connectable Calculation favourable case:
section* Suspended aerial lines (standardised routing No. 17)
PVC insulated cable
Section Section**
mm² (per phase) mm² (per phase)
20 1 x 35 1 x 2.5
25 1 x 35 1 x 2.5
30 1 x 35 1 x 4
35 1 x 35 1 x 4
40 1 x 35 1 x 6
45 1 x 35 1 x 6
50 1 x 35 1 x 10
60 1 x 35 1 x 10
70 1 x 35 1 x 16
80 1 x 35 1 x 16
90
1 x 35 1 x 25

7 - WATER CONNECTIONS

For size and position of the heat exchanger water inlet and
outlet connections refer to the certified dimensional drawings
supplied with the unit. The water pipes must not transmit any
radial or axial force to the heat exchangers nor any vibration.
The water supply must be analysed and appropriate filtering,
treatment, control devices, isolation and bleed valves and
circuits built in, to prevent corrosion, fouling and deteriora-tion
of the pump fittings. Consult either a water treatment specialist
or appropriate literature on the subject.

7.1 - Operating precautions

The water circuit should be designed to have the least number
of elbows and horizontal pipe runs at different levels. Below the
main points to be checked for the connection:
• Comply with the water inlet and outlet connections shown
on the unit.
• Install manual or automatic air purge valves at all high
points in the circuit(s).
• Use a pressure reducer to maintain pressure in the
circuit(s) and install a safety valve as well as an expan-sion
tank. Units with hydronic module include the safety valve
and expansion tank.
• Install drain connections at all low points to allow the
whole circuit to be drained.
Max. length for Cable type
voltage drop <5%
m
60 PVC Cu
60 PVC Cu
80 PVC Cu
80 PVC Cu
100 PVC Cu
100 PVC Cu
120 PVC Cu
120 PVC Cu
140 PVC Cu
140 PVC Cu
170 PVC Cu
6.4.1 - Field control wiring
Refer to the BW10 Control manual and the certified wiring
diagram supplied with the unit for the field control wiring of
the following features:
• Remote on/off switch
• Remote heat/cool switch
• Demand limit external switch 1
• Remote dual set point
• Alarm report
• Pump control - unit without hydronic module.
• Relief boiler or electric heater
• Valve control (refer to the description of options 153 and 154
in the BW10 Control manual)
Calculation unfavourable case:
Conductors in conduits or multi-conductor cables in closed conduit
(standardised routing No. 41)
PVC insulated cable, if possible
Section** Max. length for voltage drop
<5%
mm² (per phase) m
1 x 4 100
1 x 4 100
1 x 6 120
1 x 6 120
1 x 10 150
1 x 10 150
1 x 16 180
1 x 16 180
1 x 25 205
1 x 25 205
1 x 35 225
• Install stop valves, close to the entering and leaving water
connections.
• Use flexible connections to reduce the transmission of
vibrations.
• If the insulation provided is not sufficient, insulate the
cold-water piping, after testing for leaks, both to reduce
heat loss and to prevent condensation.
• Cover the insulation with a vapour barrier. If the external
water piping to the unit is in an area where the ambient
temperature can fall below 0°C, it should be insulated and
an electric heater should be installed on the piping.
NOTE: For units without hydronic module a screen filter
must be installed as close as possible to the heat exchanger and
in a position that is easily accessible for removal and
cleaning. Units with a hydronic module are equipped with this
filter.
The mesh size of the filter must be 1.2 mm. If this filter is not
installed, the plate heat exchanger can quickly become
contaminated at the first start-up, as it takes on the filter
function, and correct unit operation is affected (reduced
water flow due to increased pressure drop).
Before the system start-up verify that the water circuits are
connected to the appropriate heat exchangers (e.g. no reversal
between evaporator and condenser).
Cable type***
PVC Cu
PVC Cu
PVC Cu
PVC Cu
PVC Cu
PVC Cu
PVC Cu
PVC Cu
PVC Cu
PVC Cu
PVC Cu
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