IOMM AGR AGR 055A through 100A 9
Figure 5, Typical field evaporator water piping
Flow Switch
Mount a water flow switch in either the entering or leaving (recommended) water line to shut down
the unit when water flow is interrupted.
A flow switch is available from McQuay (part number 0017503300). It is a “paddle” type
switch and adaptable to any pipe size from 3” (76mm) to 8” (203mm) nominal. Certain minimum
flow rates are required to close the switch and are listed in Table 3. Installation should be as shown
in Figure 6. Connect the normally open contacts of the flow switch in the unit control center at
terminals 5 and 6. There is also a set of normally closed contacts on the switch that can be used for
an indicator light or an alarm to indicate when a “no flow” condition exists. Freeze protect any flow
switch that is installed outdoors.
NOTE: Differential pressure switches are not recommended for outdoor installation.
Table 3, Flow Switch Minimum Flow Figure 6, Flow switch installation
NOMINAL PIPE SIZE MINIMUM REQUIRED
FLOW TO
INCHES (MM) ACTIVATE SWITCH -
GPM (L/S)
3 (76.20 30.00 (1.90)
4 (101.6) 39.70 (2.50)
5 (127.0) 58.70 (3.70)
6 (152.4) 79.20 (5.00)
Water Connections
Bring water piping to the evaporator through the side, between the vertical supports.
Refrigerant Charge
All units are designed for use with R-22 and other refrigerants. See nameplate for specific
refrigerant used. Units are shipped with an operating charge and ready for operation. The
operating charge
(using R-22) for each unit is shown in the Physical Data tables beginning on page 13.
Flow direction
marked on switch
1" (25mm) NPT flow
switch connection
Tee
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