Carrier 19DA - Manual (Page 3)

5. Repair any leaks found.
6. Reinspect joints and flanges with the leak de­
tector to ensure that all leaks have been found
and repaired.
Machine Dehydration - The refrigerant side of
the 19DA machine is dehydrated at the factory.
It is usually not necessary to repeat dehydration
at initial start-up. However, if the machine has
been open for a considerable length of time due
to compressor removal, or if there was excessive
loss of shipping vacuum, it is recommended that
dehydration be repeated.
WARMING: Do not start compressor or oil
pump even for a rotation check while machine ;
is under dehydration vacuum.
NOTE: Dehj'dration is rea'dily accomplished at
normal room temperature. If room temper­
ature is high, dehydration takes pbace more
quickly. At low room temperature, dehydra­
tion is extremely difficult and special tech­
niques must be applied. Contact your Carrier
representative.
Perform dehydration as follows:
1. Connect dehydration pump to the cooler charg­
ing valve (Fig. 1).
2. Ensure that all valves on the purge assembly
are closed (Fig. 2). Purge valve Identification
numbers are found on the purge valve opera­
tion plate at the valves.
3. Remove the A-B swing connection (shown under
Valve Locations on the purge valve operation
plate) and connect a mercury manometer (ab­
solute pressure type) to the bottom common
connection.
4. Operate dehydration pump until manometer
reads 0.20 in. Hg (29.80 inches of vacuum
at 30 inches barometer); continue to operate
pump for two more hours.
5. Close cooler charging valve; stop dehydration
pump; record manometer reading.
6. After a two hour waiting period, take another
manometer reading. If reading has not in­
creased, dehydration is complete. If reading
has increased, repeat steps 4 and 5.
7. If the reading continues to rise after several
dehydration attempts, suspect a machine leak.
If this is the case, repeat the refrigerant
pressure test.
Inspect Piping - Refer to piping diagrams pro­
vided in Job Data and inspect chilled water piping,
condenser water piping, and water piping to oil
cooler. Ensure that flow direction is correct in
all cases and that all specified piping require­
ments are met.
CHECK WATER FLOW RATE - Water flows thru
cooler and condenser must meet job require­
ments. Measure water pressure drop across
cooler and condenser or across the pumps. Check
to see that water flow rates agree with the de­
sign flow.
Follow the instructions on the caution tag
attached to the oil cooler which reads:
CAUTION: Clean water at 85 F maximum
temperature to be provided. Valves and/or
controls to limit the following:
Max inlet working press. 100 psi
Water vel in tube, ft/sec
10 max - 6 min ;
Water flow, gaL/min 7 max - 4 min :
Water press, drop, psi diff 5 max - 2 min ;
The necessary valves and/or controls are
field supplied.
Field Wiring - Prior to starting equipment, refer
to wiring diagrams provided in Job Data and
check power supply as follows:
1. Connect a voltmeter across power wires to
compressor motor starter and measure volt­
age. Compare this reading with voltage rating
on compressor and starter nameplates.
2. Connect voltmeter across power wires to oil
pump starter and measure voltage. Compare
this reading with voltage rating on oil pump
nameplate.
3. Compare ampere rating on starter nameplate
with ampere rating on motor nameplate for
agreement.
4. Test motor and motor supply cable insulation
resistance using a five-hundred volt insulation
tester such as a megohmeter. Proceed as
follows:
a. Open starter main disconnect switch.
b. Test the three phases of compressor motor,
phase to phase, and phase to ground, with
tester connected on the motor side of the
starter contactor in the starter. Take re­
sistance readings at ten-second and sixty-
second intervals for each phase.
c. Divide sixty-second resistance reading by
ten-second reading. This gives polarization
ratio. The polarization ratio must be 1.15
or higher. The ten-second and sixty-second
resistance readings must be 5.0 megohms
or higher.
NOTE: The above procedure will check condi­
tion of compres-sor motor and motor supply
cable insulation. If above requix'ements are
not met, repeat the test at motor terminals
with motor supply cables disconnected.