Carrier 5F - Manual (Page 14)

HEATING A COOLING
5F,H
Open-Drive Compressors
Start Compressor — Close main power switch
supplying current to the compressor motor.
Immediately recheck oil level and check oil pressure.
Pressure should exceed suction pressure by 45-55 psi.
If correct pressure is not reached in 10-12 seconds, stop
compressor immediately and check oil pump.
A CAUTION
If any safety device shuts down the compressor, do
not reset the control more than once before deter­
mining cause of shutdown.
Check Control Operation — Refer to Carrier
Standard Service Techniques Manual, Chapter 2, for
complete instructions on checking electrical components.
HIGH- AND LOW-PRESSURE SWITCHES — A115F
and 5H units except 5F20 and 30 have factory-installed,
automatic reset, high- and low-pressure switches. (These
switches are available as accessories for 5F20 and 30
units.) Figure 13 illustrates adjustment procedures for
both switches.
Check High-Pressure Switch — Throttle the con­
denser water on water-cooled unit or block the airflow
on air-cooled unit, allowing head pressure to rise grad­
ually. Compressor should shut off within 15 psi of cutout
value listed in Table 4. Now reverse procedure; com­
pressor should start within 10 psi of cut-in value given.
Check Low-Pressure Switch — Slowly close the
suction service valve; suction pressure will decrease.
Compressor should shut off within 4 psi of cutout value
listed in Table 5. Reverse procedure; compressor should
start within 6 psi of cut-in value given.
Table 5 — Typical Pressure Switch Settings
REFRIG­
ERANT
CONDENSER
PRESSURESTAT
Hi!
(ps g)
Low
(psig)
Cutout Cut-in Cutout Cut-in
Water-Cooled 175 95 16 76
Air-Cooled 225 145 16 76
Water-Cooled 280 200 36 96
Air-Cooled 325 245 36 96
Water-Cooled 280 200 45 105
Air-Cooled 325 245 45 105
OIL PRESSURE SAFETY SWITCH — To check, move
contact arm at left side of switch forward (Fig. 14).
Compressor should stop in approximately 45 seconds.
If compressor continues to run, check the wiring to
safety switch. If wiring is correct, switch is faulty and
should be replaced.
After completing test, wait 3 minutes; then press
restart button on front of safety switch and restart
compressor.
Check oil level in compressor sight glass after 15-20
minutes of operation. If the oil level is low, add oil by the
methods described in Carrier Standard Service Tech­
niques Manual, Chapter 1, Section 1-11.
If an accessory oil cooler is provided, adjust the
water flow as required to maintain a lOOF to 120F
crankcase return oil temperature.
ROBERTSHAW
A-RANGE ADJUSTMENT SCREW
TOP
B-DIFFERENTIAL ADJ SCREW
0'^B-
RANCO
A-RANGE ADJUSTMENT SCREW
TOP
DIFFERENTIAL ADJ SCREW
Screw A raises or lowers both cutout and cut-in points by a like
amount.
Range and Differential scales are on the front of the switch.
High Pressure Set
cutout point first, with screw A; then set
cut-in point with screw B
Low Pressure: Set cut-in point first, with screw A, then set
cutout point with screw B
LOCATION AND ADJUSTMENTS
Fig. 13 — High- and Low-Pressure Switches
For additional information, see Oil Safety Switeh
Accessory Package Installation Instructions.
Adjust Capacity Control (if required) — See
Fig. 17 for unloading sequence.
5F20 AND 5F30 COMPRESSORS ^ Referto Capacity
Control Valve Installation Instructions for additional
information.
5F40 THROUGH 5H126 COMPRESSORS — Deter­
mine the refrigerant usage:
If the system is to use R-I2, replace the 11-lb range
adjustment spring (Fig. 15) with the 7-lb spring .supplied
with compressor. A change in 1982 reversed which range­
adjusting spring a customer received. The R-22/R-502
spring is now standard with the compressor. See instruc­
tion tag for spring replacement procedure.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without Incurring obligations.
Book! 2 PC111 Catalog No 530-526 PrIntedInUSA Form5F,H-11SI Pg14 2-86 Replaces: 5F,H-9SI
For replacement items use Carrier Specified Parts. Tab 2a