D
–EIMWC00803-21_01EN - 18/57
Table 1 - Flow switch 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.
Freeze Notice: Neither the evaporator nor the condenser is self-draining; both must be blown out to
help avoid damage from freezing.
The piping should also include thermometers at the inlet and outlet connections and air vents at the high points.
The water heads can be interchanged (end for end) so that the water connections can be made at either end of the unit. If
this is done, new head gaskets must be used and control sensors relocated.
In cases where the water pump noise can be objectionable, vibration isolation sections are recommended at both the inlet
and outlet of the pump. In most cases, it will not be necessary to provide vibration eliminator sections in the condenser
inlet and outlet water lines. But they can be required where noise and vibration are critical.
4.6.6
Cooling Towers
The condenser water flow rate must be checked to be sure that it conforms to the system design. If tower fan control is not
adequate, a tower bypass valve is recommended. Unless the system and chiller unit are specifically for condenser bypass
or variable condenser flow is not recommended since low condenser flow rates can cause unstable operation and
excessive tube fouling. Tower water treatment is essential for continued efficient and reliable unit operation. If not available
in-house, competent water treatment specialists can be contracted.
4.7
Water treatment
Table 2 - Acceptable water quality limits
DAE Water quality requirements
Shell&tube
Flooded
BPHE
Ph (25 °C)
6.8 ÷ 8.4
7.5
– 9.0
Electrical conductivity [μS/cm] (25 °C)
< 800
< 500
Chloride ion [mg Cl- / l]
< 150
< 300
Sulphate ion [mg SO42- / l]
< 100
< 100
Alkalinity [mg CaCO3 / l]
< 100
< 200
Total Hardness [mg CaCO3 / l]
< 200
75 ÷ 150
Iron [mg Fe / l]
< 1
< 0.2
Ammonium ion [mg NH4+ / l]
< 1
< 0.5
Silica [mg SiO2 / l]
< 50
NO
Chlorine molecular (mg Cl
2
/l)
< 5
< 0.5
