Carrier 30HS Series Installation, Start-Up And Service Instructions Manual page 7

Standard Service Techniques Manual, Chapter 1,
Refrigerants. One method is shown below.
To Add Oil —
Close suction shutoff valve and
pump down crankcase to 2 psig. (Low pressure
cutout must be jumpered.) Wait a few minutes and
repeat as needed until pressure remains at 2 psig.
Remove oil-fill plug above bull's-eye, add oil thru
plug hole and replace plug. Run compressor for
about 20 minutes and check oil level.
-÷ Use only Carrier-approved compressor oil:
Sun Oil Co. Suniso 3 G S
Texaco, Inc.
Capella WFI-32-150
E.I. DuPont Co. Zephron 150 (synthetic)
Do not reuse oil that has been drained and do
not use oil that has been exposed to atmosphere.
To Remove Oil —
Pump down compressor to
2 psig. Loosen the 1/ 4-in. pipe plug in compressor
base and allow oil to seep out past plug threads.
Crankcase will be under slight pressure. Be
careful not to remove plug; the entire oil charge
may be lost.
Small amounts of oil can be removed thru oil
pump discharge connection while compressor is
running.
CRANKCASE HEATERS
Heaters are furnished on all compressors to
prevent accumulation of liquid refrigerant during
shutdown. On 60-Hertz units, heaters are 115
volts; each is 125 watts. On each compressor, heater
is located in the bottom cover and held in place by
clip and bracket. Make sure heater is tight to prevent
backing out
(heater will eventually burn out if
exposed to air).
Heater is wired into control circuit,
connected to normally closed contacts on crankcase
heater relay, to energize when compressor shuts off.
De-energizing Crankcase Heater — Crankcase
heaters should be energized at all times when unit
is not operating.
However, during a prolonged shut-
down, servicing, heaters may be de-energized pro-
viding compressor service valves are closed. When
operation is to resume service valves must be re-
opened and heaters should be energized for 24 hours
before unit start-up.
COMPRESSOR REPLACEMENT
If a replacement 6-cylinder compressor has center-
bank cylinder head with discharge valve pad
facing pump end, remove head and install reverse
flange head from original compressor (discharge
valve pad toward motor end). Center-bank cylinder
head cannot be rotated 180°.
CIRCUIT BREAKERS
One breaker for each compressor provides 3-leg
overload protection. Do not bypass connections or
increase size of breaker to correct trouble. Determine
cause of trouble and correct before resetting breaker.
Tripped breaker must be manually reset by throwing
switch OFF, then ON again. See circuit breaker must
trip amps (MTA) in Table 2, Electrical Data.
MOISTURE-LIQUID INDICATOR
Clear flow of liquid refrigerant indicates suffi-
cient charge in system. Bubbles indicate under-
charged system or presence of noncondensables.
Moisture, measured in parts per million (ppm), in
system will change color of indicator.
Green —
moisture is below 45 ppm; chartreuse (caution) —
45 to 130; yellow (wet) — above 130. Change filter-
drier cores at first sign of moisture in system. Each
refrigerant circuit has an indicator.
With unit running, indicating element must be in
contact with
liquid
refrigerant to give true mois-
ture indication. 30HS units (shipped with holding
charge only) must be fully charged and run before
moisture content can be determined.
LIQUID LINE SOLENOID VALVE
One valve in each refrigerant circuit prevents
liquid refrigerant from migrating to the cooler dur-
ing shutdown.
THERMOSTATIC EXPANSION VALVES
These valves control flow of liquid refrigerant by
maintaining constant superheat of vapor leaving
cooler. Factory set to maintain a superheat of 8 to
10 F; do not adjust setting unless absolutely neces-
sary. There is one valve for each refrigerant circuit.
COMPRESSOR THERMAL PROTECTION
A discharge thermostat, installed in one cylinder
head of each compressor, senses an overtemperature
condition. If the discharge gas temperature of any
compressor exceeds 295 ± 5 F, the thermostat
opens and shuts off that compressor and the other
compressor in circuit. The thermostat reset
temperature is approximately 250 F. See Fig. 4 for
switch connections.
DTI
DT2
TB7
TB7 TB7
30HR, HS 070 - 160
CIRCUIT NO.1
TB4
30HR, HS 070-090
DT3 DT4
T84 TB4 TB4
30HR, HS 100-160
CIRCUIT NO.2
DT — Discharge Temperature Switch I 1 Terminal on unit
TB — Terminal Block (unit)
terminal block
Fig. 4 — Discharge Temperature
Switch Connections
OIL PRESSURE SAFETY SWITCH
Control (Fig.'5) is standard on 30HS units (on
compressor no. 1 and 3 only); accessory for 30HR
(see Table 3 for wiring connections).
Before initial start-up and at scheduled intervals
thereafter test be the time-delay switch.
Before testing, shield the control to prevent
moving air from contacting the time-delay switch as
this is a thermal device and moving air will affect
timing.
DT3
TB4
7