Carrier 30HL - Compressor Control & Safety Features; Time Guard Control; Oil Pressure Safety Switch (OPS)

The electric heater is wired into the 115-volt
control circuit thru normally closed contacts of
control relay in such a way that it is energized only
when compressor is not operating.
All heaters are 125 watts.
CAU*! iON: Never open any switch or discon¬
nect that will de-energi/c ciankca^e heatci un¬
less unit IS being serviced or will be shut down
for a prolonged period. After such service or
prolonged shutdown, cnergi/c crankcase heater
loi 24 hours bclore starting compressor
TIME GUARD® CONTROL
This control protects compressor against short
cycling (Switch A on four-function timer).
FOUR-FUNCTION TIMER
Refer to Fig. 4 — Timer Cycle. The functions are
as follows:
Switch A (Contacts A-Al, A-A2) runs timer motor.
This provides a minimum of 5-1/2 minutes after
compressor stops before it can restart, to prevent
short cycling (Time Guard control).
Switch B (Contacts B-Bl, B-B2) provides 1-second
time delay for part-winding start and also provides
a lock-out function.
Switch D (Contacts D-D 1) provides a 2-1 / 2 minute
bypass of the low-pressure switch at start-up to
prevent nuisance trips under cold-start conditions.
Switch E (Contacts E-El) provides a 35-second by¬
pass of the oil safety switch (OPS) at compressor
start-up (when OPS is used), if sufficient oil pressure
does not build up in this time, compressor stops.
SWITCH POSITION |
PRESSURE SETTING
Close on rise
i 9 - 1 2 psi d)ff
1 4 - 6 psi diff
The oil pressure safety switch is wired in parallel
with Switch E of the 4-function timer. This arrange¬
ment allows approximately 35 seconds for oil pres¬
sure to reach normal operating level after com¬
pressor starts. If the oil safety switch does not close
within 35 seconds, the compressor shuts down.
To restart the compressor, the control circuit
ON-OFF switch must be pressed to OFF and then to
ON. The timer will start and after approximately
5-1/2 minutes compressor will start, if normal oil
pressure is established within the next 35 seconds,
the compressor continues to run. if, however, the oil
pressure does not reach a safe level, the compressor
stops at the end of the 35 seconds and locks out.
CAUTION: Do not attempt to restart the com-
prcNSor lor a .second lime until the pioblem has
been determined and corrected.
REMOVE ORANGE Wl RE
EE|
7 SEC±4
+-H 1-^5 SEC
DDI
-40SEC15 !
—I
NOTE: BLACK DENOTES CLOSED CONTACTS
Fig. 4 — Timer Cycle
OIL PRESSURE SAFETY SWITCH (OPS)
This control is standard on 30HL (condenserless)
units (020-030) and is available as an accessory for
30HK units (020-030). Refer to Fig. 5 for field
wiring connections. It is not available for the 015
unit.
The pressure switch is factory set at the following
pressures and should not be adjusted in the field.
OPS — Oil Pressure Safety Switch
TB — Terminal Board
Fig. 5 — Oil Pressure Safety Switch to
Control Box Wiring Connections
(020-030 Only)
LOW LIMIT STOP TAB
Fig. 6 — Safety Thermostat
(No. HH22CC050 Shown)
9
1090