IOM 686 AGZ 030A through 065A 9
Flow Switch
Mount a water flow switch in either the entering or leaving 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 rates
NOMINAL PIPE SIZE MINIMUM REQUIRED FLOW TO
INCHES (MM) ACTIVATE SWITCH - GPM (L/S)
1 (25.4) 6.00 (0.38)
11/4 (31.8) 9.80 (0.62)
11/2 (38.1) 12.70 (0.80)
2 (50.8) 18.80 (1.20)
21/2 (63.50 24.30 (1.50)
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)
Figure 6, Flow switch installation
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. The operating charge
(using R-22) for each unit is shown in the Physical Data tables beginning on page 13.
Superheat and Subcooling
For optimum operation, set the evaporator superheat for 8 - 12°F (4.4 - 6.6°C) and condenser
subcooling (at the liquid shutoff valves) to 15°F (8.3°C).
Flow direction
marked on switch
1" (25mm) NPT flow
switch connection
Tee
To Next Page
Loading...
Need help?
General
