Carrier 19DG - Manual (Page 6)

Table 2 — Setting Safety Controls
SAFETY OR CONTROL DEVICE
1. Chilled Water Low-Temperature Cutout and
Recycle Switch (Fig. 1)
-TEMPERATURE ADJUSTMENT
Set this switch to break at approximately 5 F below design
chilled water temperature, or at 36 F whichever is higher
Set the differential at 10 +1 F so that when the machine shuts
down automatically at approximately 5 F below the design
chilled water temperature it will restart at approximately 5 F
above the design water temperature.
This control must break ahead of the refrigerant low-temperature
cutout switch or the machine will not recycle automatically
SAFETY OR CONTROL DEVICE
STOP MACHINE, REMOVE JUMPERS AND PERFORM RE­
MAINING CHECKS
4. Oil Heater Thermostat (Fig. 1)
LOCKING
SCREW
Set the oil heater thermostat to maintain a minimum oil reservoir
temperature of 145 F at shutdown
2. Refrigerant Low-Temperature Cutout (Fig. 1)
CUTOUT
ADJUSTMENT
Set refrigerant low-temperature cutout at 33 F or one degree below
design refrigerant temperature, whichever is lower, while checking
temperature at thermowell near switch
3. Condenser High-Pressure Cutout (Fig. 3)
CUTOUT ADJUSTMENT
COVER
RESET
BUTTON
CUTOUT SCALE
The condenser high-pressure cutout is factory set to shut the ma­
chine down when condenser pressure reaches approximately 1 5 psig.
Isolate the switch and check setting with a metered supply of air
5. Low Oil Pressure Cutout (Fig. 3)
RANGE
DIAL ADJUSTMEN'
REMOVE METAL
COVER
DIFFERENTIAL-
OIL
PRESSURE
Low oil differential pressure switch is factory set to open at 9 5 ± 1
psi and close at 1 4 5 ± 1 psi differential pressure
6. Vane-Close Oil Pressure Switch (Fig. 3)
RANGE ADJUSTMENT
Vane-close oil pressure switch is factory set to close at 18.5 psi dif­
ferential pressure (on rise) and open on a 0.5 psi drop in dif­
ferential pressure Switch does not require field calibration