Operation; Sequence Of Operation; Dual Chiller Sequence Of Operation - Carrier AquaForce 30XV140 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

OPERATION

Sequence of Operation —
chiller, the evaporator 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 de-energize the oil separator heater (if already energized).
The control will continue to load this circuit by increasing the
VFD frequency to satisfy cooling requirements. Once fully
loaded, the control will start the second circuit to satisfy load as
required. Shutdown of each circuit under normal conditions oc-
curs in the opposite sequence to loading. Once a circuit is fully
unloaded the compressor is shut off and the EXV will close
completely.
ACTUATED BALL VALVE (ABV) —
equipped with this option (standard in most regions), either one
or two discharge ABVs are located in the discharge line of each
circuit of the unit. See Fig. 40 for a typical ABV assembly with
enclosure. The ABV is a motorized ball valve, which is used to
close the discharge line to prevent refrigerant migrating from
condenser to the evaporator when the circuit is off. The valve
will be opened before the compressor is started and will nor-
mally close when pressure equalizes between suction and dis-
charge lines.
The actuated ball valves are linked to the evaporator heater
operation in the controls. Evaporator Heater option (Main

Menu Configuration Menu
rator Heater Installed = yes) must be enabled for the actuated
ball valve to operate.
See Fig. 41 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. 42 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 Disengagement
(Push) button. See Fig. 42.
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.
Dual Chiller Sequence of Operation —
command to start the chiller, the master chiller determines
which chiller will become the lead chiller based on the con-
figuration of Lead Lag Select (lead_sel) and Lead/Lag Bal-
ance Delta (ll_bal_d). The lead chiller is always started first
and the lag chiller is held at zero percent capacity by the
master chiller forcing the lag demand limit value to 0%. If
Lead Pulldown Time (lead_pul) has been configured, the
lead chiller will continue to operate alone for that specified
time. After the Lead Pulldown Time timer has elapsed and
when the lead chiller is fully loaded, either all available
compression is on or at the master demand limit value, then
the lag start timer (lstr_tim) is initiated.
With a command to start the
For chillers
 
Factory Parameters Evapo-
With a
VALVE MOTOR COVER
VALVE MOTOR
BASE PLATE
Fig. 40 — Typical ABV Assembly with Enclosure
VALVE SHAFT
Fig. 41 — Fully Open Ball Valve
with Actuator Removed
MOUNTING - FULLY CLOSED
ACTUATOR ARM
CLAMPING SCREW
MOUNTING - FULLY OPEN
Fig. 42 — Ball Valve Motor
47
a30-4236
a30-4237
DISENGAGEMENT
BUTTON
a30-4238