Refrigerant Circuit; Safety Devices; Compressor Protection; Oil Separator Heaters - Carrier AquaForce 30XV140 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

Refrigerant Circuit

LEAK TESTING — Units are shipped with complete oper-
ating charge of refrigerant R-134a (see Physical Data tables
supplied in the 30XV installation instructions) and should
be under sufficient pressure to conduct a leak test. If there is
no pressure in the system, introduce enough nitrogen to
search for the leak. Repair the leak using good refrigeration
practices. After leaks are repaired, system must be evacuat-
ed and dehydrated.
REFRIGERANT CHARGE — Refer to Physical Data tables
supplied in the 30XV installation instructions. Immediately
ahead of filter drier in each circuit is a factory-installed liquid
line service valve. Each valve has a
for charging liquid refrigerant.
Charging with Unit Off and Evacuated — Close liquid line
service valve before charging. Weigh in charge shown on unit
nameplate. Open liquid line service valve; start unit and allow
it to run several minutes fully loaded. Check for a clear sight
glass. Be sure clear condition is liquid and not vapor.
Charging with Unit Running — If charge is to be added while
unit is operating, all condenser fans and compressors must be
operating. It may be necessary to block condenser coils at low
ambient temperatures to raise condensing pressure to approxi-
mately 198 psig (1365 kPa) to turn all condenser fans on. Do not
totally block a coil to do this. Partially block all coils in uniform
pattern. Charge each circuit until sight glass shows clear liquid,
and has a liquid line temperature of 103 F (39 C).
Add 3 to 5 lb (1.36 to 2.27 kg), depending on unit size and-
coil type, of liquid charge into the fitting located on the tube en-
tering the evaporator. This fitting is located between the elec-
tronic expansion valve (EXV) and the evaporator.
Allow the system to stabilize and then recheck the liquid
temperature. If needed, add additional liquid charge, 3 to 5 lb
at a time, allowing the system to stabilize between each charge
addition. Slowly add charge as the sight glass begins to clear to
avoid overcharging.
IMPORTANT: When adjusting refrigerant charge, circu-
late fluid through evaporator continuously to prevent
freezing and possible damage to the evaporator. Do not
overcharge, and never charge liquid into the low-pressure
side of system.
The 30XV chillers contain many
Safety Devices —
safety devices and protection logic built into the electronic
control. Following is a description of the major safeties.

COMPRESSOR PROTECTION

Motor Overload — The compressor VFD fuses and drive
logic protect each compressor against overcurrent.
All compressors have factory-installed high-pressure
switches. See Table 39. Each high-pressure switch is connected
directly to its associated VFD (terminals 12 and 37). If the
switch opens during operation, the compressor will be shut
down. Manual reset of the high pressure switch, VFD, and the
control is required to restart the compressor.
Table 39 — High-Pressure Switch Settings
SWITCH SETTING
UNIT
psig
30XV 323.5 + 0.0 –14.0
OIL SEPARATOR HEATERS — Each oil separator circuit
has a heater mounted on the side of the vessel. The heater is
de-energized any time the compressor is on. If the compres-
sor is off and outdoor-air temperature (OAT) is greater than
100 F (37.8 C) the heater is de-energized. The heater will
also be de-energized if OAT – SST > 30 F (16.7 C) and the
OAT –LWT > 30 F (16.7 C).
1 / -in. access connection
4
kPa
2230 + 0.0 –14.0
63
Fusible plugs are located in each cir-
Relief Devices —
cuit between the condenser and the liquid line shutoff valve.
PRESSURE RELIEF VALVES — Valves are installed in
each circuit and are located on the evaporators and oil sepa-
rators. These valves are designed to relieve if an abnormal
pressure condition arises. Relief valves on all evaporators
relieve at 220 psig (1517 kPa). Relief valves on oil separa-
tors relieve at 350 psig (2413 kPa). These valves should not
be capped. If a valve relieves, it should be replaced. If the
valve is not replaced, it may relieve at a lower pressure, or
leak due to trapped dirt from the system which may prevent
resealing. See Table 40. Some local building codes require
that relieved gases be exhausted to a specific location. This
connection allows conformance to this requirement.
Table 40 — Relief Valve Connection Specifications
LOCATION
Oil Separator
Evaporator
Inspection and Maintenance — The relief valves on this
chiller protect the system against the potentially dangerous
effects of overpressure. To ensure against damage to the
equipment and possible injury to personnel, these devices
must be kept in peak operating condition. As a minimum,
the following maintenance is required:
1. At least once a year, disconnect the vent piping at the
valve outlet if equipped. Inspect the vent piping for
corrosion, a restriction or blockage. If any is found,
clean or replace the affected vent piping.
2. Carefully inspect the valve body and mechanism for any
evidence of internal corrosion or rust, dirt, scale, leakage,
etc. If corrosion or foreign material is found, do not at-
tempt to repair or recondition; replace the valve.
3. If the chiller is installed in a corrosive atmosphere or
the relief valves are vented into a corrosive atmo-
sphere, inspect relief valves and piping at more fre-
quent intervals.
Variable Frequency Drives (VFDs) —
units with Greenspeed ® intelligence are equipped with variable
frequency drives (VFDs) to control the compressors and con-
denser fans. The Danfoss VLT* HVAC drives each include an
LCD user interface display. However, all necessary functions
and statuses can be accessed from within the Touch Pilot™
menus. The VFDs are configured through the Touch Pilot con-
trols, and parameters should not be changed manually.
COMPRESSOR DRIVES — Each unit is equipped with two
VFDs to control the compressor operation, one for each cir-
cuit. The VFDs vary the operating speed of the compressors
by changing the input power frequency over a programmed
range. The compressor VFDs should not be operated below
minimum programmed frequency, to ensure adequate oil re-
turn on the unit. When looking at the end of the unit, the Ckt
A drive is closer to the control panel. See Fig. 60 for com-
pressor VFD locations.
For chillers 140-325 tons, the VFDs are equipped with
an aluminum enclosure to protect the drive from outdoor
conditions. The cover must be removed to access the LCD
user interface display or to service the drive. The cover is
secured with 6 screws. See Fig. 61 for details on how to re-
move or reinstall the drive cover.
CONNECTION SIZES
3/8 SAE Flare
3/4 in. NPT Female
The 30XV