7.4.10 Drycooler Settings; Table 8 Water/Glycol System Conditions Requiring Optional Settings For Aquastats; Table 9 Aquastat Settings-Two-Fan Through Four-Fan Drycoolers - Emerson Liebert Challenger 3000 Operation & Maintenance Manual

Manual Flushing—The valve may be flushed by rotating the socket head screw clockwise. This
screw must be in the OUT position (counterclockwise) for normal valve operation.
Valve Disassembly
1. Shut off the water supply by using isolating valves.
2. Relieve the tension on the main spring by turning the adjusting screw (or collar) as far as it will
go (provide a container to catch water below the valve).
3. Remove four screws extending through the main spring housing.
4. Remove the center assembly screws for access to all internal parts.
5. Clean the seat if possible. If the seat is pitted or damaged, replace the valve rubber disc and valve
seat.
6. After valve is reassembled check for leaks.
7. Readjust head pressure control.
Testing Function of Valve—When the refrigeration system has been Off for approximately 10 to 15
minutes, the water flow should stop.
If the water continues to flow, the valve is either improperly adjusted (with head pressure too low) or
the pressure sensing capillary is not connected properly to the condenser.

7.4.10 Drycooler Settings

Applications with the Optional Stat Setting require field piping to be insulated to prevent condensa-
tion. Table 8 shows acceptable applications where stats must be adjusted to Optional Setting.
Aquastats must be field-adjusted to Optional Setting for:
• GLYCOOL/Dual Cool applications
• Single Drycooler loops with motor ball valve flow controls (motor ball valves are used on all Lie-
bert Challenger 3000 and ITR units with digital compressors).
Table 8 Water/glycol system conditions requiring optional settings for aquastats
Cooling Type
Flow Control
Drycoolers in Loop
1
Stat Setting
Insulate Field Piping
1. See Table 9.
2. MBV=motor ball valve; WRV=water regulating valve
Table 9 Aquastat settings—two-fan through four-fan drycoolers
Dial Setting (Stat Open Temp) Set for Mid Differential 8°F (4.4°C) Rise to Close
Aquastat #
AQ1
AQ2
AQ3
NOTE
1. All drycoolers are shipped at Factory Setting.
2. Factory Setting is used for all glycol applications, except single drycooler loops with motor
ball valve controls.
3. Stats must be field-adjusted to Optional Setting for GLYCOOL/Dual Cool applications
and all single drycooler loops using motor ball valve flow controls.
Glycool
MBV
1 Multiple
Optional Optional
Yes Yes
Factory Setting
Fans (Glycol) (see Notes 1 and 2)
F1 65°F (18.3°C)
F2 & F3 75°F (23.9°C)
F4 70°F (21.1°C)
Component Operation and Maintenance
WRV
1 Multiple
Optional Optional Optional
Yes Yes Yes
46
Glycol
MBV WRV
1 Multiple 1
Factory Factory
No No
Optional Setting
(GLYCOOL) (see Note 3)
35°F (1.7°C)
45°F (7.2°C)
40°F (4.4°C)
Multiple
Factory
No