Chiller Dehydration; Inspect Water Piping; Check Safety Valves; Inspect Wiring - Carrier AquaEdge 19DV series Start-Up, Operation And Maintenance Instructions Manual

Chiller Dehydration —
the chiller has been open for a considerable period of time, if
the chiller is known to contain moisture, or if there has been a
complete loss of chiller holding charge or refrigerant pressure.
CAUTION
Do not start or megohm-test the compressor motor or any
other pump motor, even for a rotation check, if the chiller is
under dehydration vacuum. Insulation breakdown and
severe damage may result.
WARNING
Power to the motor and starter must be disconnected by an
isolation switch before placing the machine under a vac-
uum. To be safe, isolate input power before evacuating the
chiller if you are not sure if there are live leads to the her-
metic motor.
Dehydration can be done at room temperatures. Using a
cold trap (Fig. 17) may substantially reduce the time required
to complete the dehydration and is recommended should the
unit be exposed to liquid moisture. The higher the room tem-
perature, the faster dehydration takes place. At low room tem-
peratures, a very deep vacuum is required to boil off any mois-
ture and heating of the water in the water circuits of the chiller
to approximately 100°F (38°C) may be required.
Fig. 17 — Dehydration Cold Trap
Perform dehydration as follows:
1. Connect a high capacity vacuum pump (5 cfm [.002 m
or larger is recommended) to the refrigerant vacuum/
charging valve (Fig. 2). Tubing from the pump to the
chiller should be as short in length with a minimum diam-
eter of 0.5 in. (13 mm) and as large in diameter as possible
to provide least resistance to gas flow.
2. Use an absolute pressure manometer or a electronic mi-
cron gage to measure the vacuum. Open the shutoff valve
to the vacuum indicator only when taking a reading.
Leave the valve open for 3 minutes to allow the indicator
vacuum to equalize with the chiller vacuum.
3. If the entire chiller is to be dehydrated, open all isolation
valves (if present).
4. With the chiller ambient temperature at 60°F (15.6°C) or
higher, operate the vacuum pump until the manometer
reads 29.8 in. Hg (vac), -14.63 psig (-100.9 kPag), or a
vacuum indicator reads 35°F (1.7°C). Operate the pump
an additional 2 hours.
Do not apply a greater vacuum than 29.82 in. Hg vac
(757.4 mm Hg) or go below 33°F (0.56°C) on the wet
bulb vacuum indicator. At this temperature and pressure,
isolated pockets of moisture can turn into ice. The slow
rate of evaporation (sublimation) of ice at these low tem-
peratures and pressures greatly increases dehydration
time.
Dehydration is recommended if
3
5. Valve off the vacuum pump, stop the pump, and record
the instrument reading.
6. After a 2-hour wait, take another instrument reading. If
the reading has not changed, dehydration is complete. If
the reading indicates vacuum loss, repeat Steps 4 and 5.
7. If the reading continues to change after several at-
tempts, perform a leak test (maximum 45 psig [310
kPa] pressure). Locate and repair the leak, and repeat
dehydration.
8. Once dehydration is complete, the evacuation process can
continue. The final vacuum prior to charging the unit with
refrigerant should in all cases be 29.9 in. Hg (500 mi-
crons, 0.07 kPa [abs]) or less.
Inspect Water Piping —
vided in the certified drawings and the piping instructions in
the 19DV Installation Instructions manual. Inspect the piping
to the cooler and condenser. Be sure that the flow directions are
correct and that all piping specifications have been met.
Piping systems must be properly vented with no stress on
waterbox nozzles and covers. Water flows through the cooler
and condenser must meet job requirements. Measure the pres-
sure drop across the cooler and the condenser.
Water must be within design limits, clean, and treated to
ensure proper chiller performance and to reduce the poten-
tial of tube damage due to corrosion, scaling, or erosion.
Carrier assumes no responsibility for chiller damage result-
ing from untreated or improperly treated water.
Check Safety Valves —
been piped to the outdoors in compliance with the latest edition
of ANSI/ASHRAE Standard 15 and applicable local safety
codes. Piping connections must allow for access to the valve
mechanism for periodic inspection and leak testing.
The standard 19DV relief devices are set to relieve at
57 psig (393 kPa) chiller design pressure. To avoid potential
rupture the chiller should never be pressurized above 45 psig
(310 kPa) for any testing purpose.

Inspect Wiring

/s]
Do not check the voltage supply without proper equipment
and precautions. Serious injury may result. Follow power
company recommendations.
Do not apply any kind of test voltage, even for a rotation
check, if the chiller is under a dehydration vacuum. Insula-
tion breakdown and serious damage may result.
1. Examine the wiring for conformance to the job wiring di-
agrams and all applicable electrical codes.
2. Compare the ampere rating on the VFD nameplate to rat-
ing on the compressor nameplate.
3. Check and record voltage across power wires to the VFD;
measure phase to phase and phase to ground. Validate
against VFD nameplate.
4. Ensure that VFDs are protected by fused disconnects or
circuit breakers as per electrical code.
20
Refer to piping diagrams pro-
CAUTION
Be sure safety valves have
WARNING
CAUTION