Operation; Sequence Of Operation; Actuated Ball Valve (Abv), Flooded - Carrier AQUAFORCE 30XA080-500 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

10
(29.9)
9
(26.1)
8
(23.2)
7
(20.3)
6
(17.4)
5
(14.5)
4
(11.6)
3
(8.7)
2
(5.5)
1
(2.9)
0
0
NOTE: Minus-one-pass coolers are not available for 30XA400-500 units.
Fig. 38D — Cooler Pressure Drop Curves, Minus One-Pass Flooded Cooler (cont)

OPERATION

Sequence of Operation —
the chiller, the cooler pump will start. After verifying water
flow, the control will monitor the entering and leaving water
temperature. If the need for mechanical cooling is determined,
the control decides which circuit and compressor to start. The
control will start the required compressor completely unloaded
and deenergize the oil separator heater (if already energized).
The control will continue to load this circuit by moving the
slide valve to satisfy cooling requirements. Once fully loaded,
the control will start additional circuits to satisfy the load as
required. Shutdown of each circuit under normal conditions
occurs in the opposite sequence to loading. Once the A circuit
is fully unloaded the compressor is shut off and the EXV will
close completely.
If the outside-air temperature is less than the brine freeze
point plus 17º F (9.4º C) then the circuit will perform a pump
down cycle. The EXV will be closed and the compressor con-
tinues to operate until the saturated suction temperature (SST)
is 10º F (5.6º C) lower than the starting SST or 10º F (5.6º C)
less than the brine freeze point. Once the compressor is shut off
the actuated ball valve (located in the discharge line) will be
closed if equipped (flooded cooler option units only).
ACTUATED BALL VALVE (ABV), FLOODED COOLER
ONLY — There is either one or two discharge ABVs located
in the discharge line of each circuit of the unit. See Fig. 39 for a
typical ABV assembly with enclosure. The ABV is a motor-
ized ball valve, which is used to close the discharge line to pre-
vent refrigerant migrating from condenser to the cooler when
the circuit is off. The valve will be opened before the compres-
sor is started and will normally close when pressure equalizes
between suction and discharge lines. If the outside air tempera-
ture is less than the brine freeze point plus 17º F (9.4º C) then
Unit Sizes 30XA260, 280, 300, 325, 350
200 400 600
(12.6) (25.2) (37.9)
COOLER FLOW, GPM (l/s)
With a command to start
260
800 1000 1200
(50.6) (63.3) (75.9)
the valve will close immediately without waiting for pressure
equalization.
The actuated ball valves are linked to the cooler heater oper-
ation in the controls. Cooler Heater option (Configuration
Unit  CO.HT , SERVICE
Select) must be enabled for the Actuated Ball Valve to operate.
See Fig. 40 for a view of a fully open ball valve with the ac-
tuator removed. The flat surface at the top of the valve shaft is
parallel to the discharge line. The ball valve motor mounting
plate should be perpendicular to the discharge line at all times.
If not, adjust it by loosening the set screw on the side of the
valve, reposition assembly and tighten set screw.
See Fig. 41 for a view of the ball valve motor mounting
with a fully open valve. The motor actuator arm should be at a
counterclockwise position, with the valve shaft in a parallel po-
sition. If not in a parallel position, loosen the clamping screw
and push the disengagement button to rotate the actuator arm
until it stops. Retighten the clamping screw.
ABV Manual Operation — The ABV can be operated manu-
ally as a discharge service valve by completing the following
steps:
1. Remove the actuator cover.
2. With the compressor off hold down the Push button.
3. Close the ABV by turning the shaft adapter by hand or
with a wrench so that the flats on the end of the shaft are
perpendicular to the discharge line.
4. Release the Push button.
5. Disconnect the control power cable to the ABV.
67
350
325
280 300
1400 1600 1800
(88.6) (101.3) (114.0)
 FACTORY  Cooler Heater
a30-4492
