Manualshelf

Specifications

ManualsBrandsCarrier ManualsRefrigeratorAQUAFORCE 30XW150-400
51525354555657585960
58
OPERATION
Sequence of Operation —
With a command to start
the chiller, the cooler and condenser pumps will start. After
verifying water flow, the control will monitor the entering and
leaving water temperatures. If the need for mechanical cooling
is determined, the control decides which circuit and compres-
sor to start. The control will start the required compressor com-
pletely unloaded. The control will continue to load this circuit
by moving the slide valve to satisfy cooling requirements.
Once fully loaded, the control will start an additional circuit
(sizes 325-400 only) to satisfy the load as required.
For those chillers configured for heat machine duty, the con-
trol will load compressors to satisfy the required heating set
point provided there is a cooling load.
Shutdown of each circuit under normal conditions occurs in
the opposite sequence to loading. Once the circuit is fully
unloaded the compressor is shut off and the EXV will close
completely.
Dual Chiller Sequence of Operation — With a
command to start the chiller, the master chiller determines
which chiller will become the lead chiller based on the configu-
ration of Lead Lag Select, LLBL and Lead/Lag Balance Del-
ta, LLBD. 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 Pulldown Time, LPUL) 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 com-
pression is on or at the master demand limit value, then the lag
start timer (Lag Start Timer, LLDY) is initiated. When the
pulldown timer and lag start timer has elapsed and the
Combined Leaving Chilled Water Temperature is more than
3° F (1.7° C) above the set point, then the lag chiller is started.
If the lag chiller’s water pump was not started when the ma-
chines went into occupied mode, the lag chiller water pump
will be started. The lag chiller will start with the master chiller
forcing the lag chiller demand limit value (LAG_LIM) to the
master’s demand limit value. If lead/lag capacity balance is se-
lected, once the lag chiller has started, the master shall try to
keep the difference in capacity between lead and lag less than
20%. The master shall then be responsible for water loop ca-
pacity calculation, and will determine which chiller, the lead or
lag, will increase or decrease capacity. When the load reduces,
the lag chiller will be the first chiller to unload. To accomplish
this, the lead chiller set point is decreased by 4° F (2.2° C) until
the lag chiller unloads.
PUMP OPERATION — For parallel chiller pump operation,
the lead chiller’s water pump will be started. The lag chiller’s
water pump will be maintained off if Lag Unit Pump Control,
LAGP=0. The internal algorithm of lead chiller will control ca-
pacity of the lead chiller.
For series chiller operation, the pump is always controlled
by the master chiller.
Operating Modes — Operating modes are override
modes that affect normal operation of the equipment. More
than one operating mode can be in effect at the same time.
Some operating modes have corresponding capacity control
overrides in the Capacity Control Overrides section on
page 44.
For the Touch Pilot display, the status of the operating
modes can be found in the MODES submenu, which is under
the STATUS menu. Each operating mode and its status (Yes =
active, No = inactive) is listed.
2 pass
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
ft wg
gpm
(L/s)
(0)
(14.9)
(29.8)
(44.8)
(59.7)
(74.6)
(89.5)
(104.4)
(119.4)
(kPa)
0 500 1000 1500 2000 2500 3000 3500
(0) (31.5) (63.1) (94.6) (126.2) (157.7) (189.3) (220.8)
Condenser Flow Rate
Pressure Drop