16
Centrifugal Chillers
D-EIMWC00804-14EN
installed in both water inlet lines. Sufficient shutoff valves must be installed to permit
draining the water from the evaporator or condenser without draining the complete system.
Flow Switch
A water flow switch must be installed to signal the presence of adequate water flow to the
vessels before the unit can start. They also serve to shut down the unit in the event that water
flow is interrupted to guard against evaporator freeze-up or excessive discharge pressure.
Thermal dispersion flow switches are available from Daikin as a factory-mounted option. It is
mounted in an evaporator and condenser water nozzle and factory wired.
A paddle type flow switch can be supplied by the owner for field mounting and wiring.
Figure 6, Flow Switch Mounting
If flow switches, by themselves, are being used, electrical connections in the Unit Control
Panel must be made from the common T3-S terminal to terminal CF for the condenser switch
and T3-S to terminal EF for the evaporator switch. See Figure 15, Field Wiring Diagram on
page 33. The normally open contacts of the flow switch must be wired between the terminals.
Flow switch contact quality must be suitable for 24 VAC, low current (16ma). Flow switch
wire must be in separate conduit from any high voltage conductors (115 VAC and higher).
Table 1, Flow Switch Flow Rates
Pipe Size
(NOTE !)
inch
1 1/4
1 1/2
2
2 1/2
3
4
5
6
8
mm
32 (2)
38 (2)
51
63 (3)
76
102 (4)
127 (4)
153 (4)
204 (5)
Min.
Adjst.
Flow
gpm
5.8
7.5
13.7
18.0
27.5
65.0
125.0
190.0
205.0
Lpm
1.3
1.7
3.1
4.1
6.2
14.8
28.4
43.2
46.6
No
Flow
gpm
3.7
5.0
9.5
12.5
19.0
50.0
101.0
158.0
170.0
Lpm
0.8
1.1
2.2
2.8
4.3
11.4
22.9
35.9
38.6
Max.
Adjst.
Flow
gpm
13.3
19.2
29.0
34.5
53.0
128.0
245.0
375.0
415.0
Lpm
3.0
4.4
6.6
7.8
12.0
29.1
55.6
85.2
94.3
No
Flow
gpm
12.5
18.0
27.0
32.0
50.0
122.0
235.0
360.0
400.0
Lpm
2.8
4.1
6.1
7.3
11.4
27.7
53.4
81.8
90.8
NOTES:
1. A segmented 3-inch paddle (1, 2, and 3 inches) is furnished mounted, plus a 6-inch paddle loose.
2. Flow rates for a 2-inch paddle trimmed to fit the pipe.
3. Flow rates for a 3-inch paddle trimmed to fit the pipe.
4. Flow rates for a 3-inch paddle.
5. Flow rates for a 6-inch paddle
6. There is no data for pipe sizes above 8-inch. A switch minimum setting should provide protection
against no flow and close well before design flow is reached.
Alternatively, for a higher margin of protection, normally open auxiliary contacts in the pump
starters can be wired in series with the flow switches as shown in Figure 15, Field Wiring
Diagram on page 33.
Flow direction marked
on switch
I in. (25mm) NPT flow
switch connection
Tee
