Daikin WDC Installation, Operation And Maintenance Manual page 69

Wiring
Refer to wiring diagram in the unit control panel.
Either AC or DC is used to power the flow switch. The unit
controller's digital input is a DC signal which is supplied
through the switch output of the flow switch for flow indication.
It is required that the AC and DC commons of power be
separated. Contact Chiller Technical Response for alternate
wiring scenarios.
Flow Switch Setup
The flow switch comes from the factory set at a default velocity
of 20 cm/s. This value is typically well below the minimum
water flow specified for the unit's evaporator and condenser so
field adjustment is required for adequate low flow protection.
Table 30 are the calculated gallons per minute (gpm) for
Schedule 40 steel pipe for various fluid velocities from 20
cm/s to 300 cm/s. The flow switch has an overall range of
adjustment from 3 cm/s to 300 cm/s.
Step 1: Adjust flow through the evaporator to the minimum
desired operating gpm. Maintain this flow throughout the setup
procedure.
Table 30: Flow Volume Calculation
Inside
Pipe Pipe
Default
Size Diameter
(inch) (inch) 20 cm/sec 30 cm/sec 50 cm/sec 75 cm/sec 100 cm/sec 150 cm/sec 200 cm/sec 250 cm/sec 300 cm/sec
2 2.06 6.86
2.5 2.46 9.79
3 3.07 15.1
3.5 3.55 20.2
4 4.03 26.0
5 5.05 40.9
6 6.07 59.1
8 7.98 102.3
10 10.02 161.3
12 11.94 229.0
14 13.13 276.8
16 15.00 361.5
18 16.88 457.5
20 18.81 572.4
Step 3: After the 'Teach' function is completed and the outer
LEDs flashed, the flow switch will indicate a new set point
based upon the current flow which should still be at the steady
state minimum desired operating flow.
typical display for this condition. All LEDs to the left of the
SP LED are lit green. The SP LED is lit RED (or may toggle
amber) which indicates that the flow switch is OPEN. Typically,
an increase in fluid flow is between 15% to 30% above the
'Teach' function flow is required for the SP LED to turn AMBER
and the flow switch to CLOSE indicating acceptable flow.
www.DaikinApplied.com
US GPM at the velocities indicated below
10.3 17.2 25.7
14.7 24.5 36.7
22.7 37.8 56.7
30.3 50.6 75.8
39.1 65.1 97.7
61.4 102.3 153.5
88.6 147.7 221.6
153.5 255.8 383.7
241.9 403.2 604.8
343.4 572.4 858.6
415.2 692.0 1037.9
542.2 903.6 1355.5
686.3 1143.8 1715.7
853.0 1421.6 2132.4
Figure 74 shows a
Step 2: Once steady state minimum desired operating flow is
obtained, perform the 'Teach' function on the flow switch. The
'Teach' function is initiated by holding down the minus '-' button
on the face of the flow switch for 15 seconds. During this 15
second period, LEDs '0' and '9' will be lit green. Once the
'Teach' function is completed, the outer LEDs will flash green
as shown in Figure 73.
Figure 73: Automatic Teach of Setpoint
34.3 51.5 68.6
49.0 73.4 97.9
75.6 113.4 151.2
101.1 151.7 202.2
130.2 195.3 260.4
204.6 306.9 409.2
295.5 443.2 590.9
511.6 767.5 1023.3
806.5 1209.7 1612.9
1144.7 1717.1 2289.5
1383.9 2075.9 2767.8
1807.3 2710.9 3614.6
2287.6 3431.4 4575.2
2843.2 4264.8 5686.4
Figure 74: Teach Adjustment Complete
69 IOM 1281-2 • CENTRIFUGAL WATER CHILLERS
Maintenance
GPM
adjustment
per '+' or '-'
key input
85.8 102.9 1.72
122.4 146.9 2.42
189.0 226.8 3.78
252.8 303.3 5.06
325.5 390.5 6.51
511.5 613.7 10.2
738.7 886.3 14.8
1279.1 1534.7 25.6
2016.2 2419.1 39.0
2861.9 3433.8 57.2
3459.8 4151.3 69.2
4518.2 5421.2 90.4
5719.0 6862.1 114.4
7108.0 8528.6 142.2