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Once the compressor is shut off, the control system pre-
vents the compressor from restarting within 5 minutes of when
it was last shut down. Once this period has elapsed and the
leaving fluid temperature rises above the set point, the com-
pressor will start within 5 seconds.
If the unit is equipped with field-installed hot gas bypass,
the hot gas bypass valve opens only when stage 1 is active.
If the unit trips out on high pressure, low pressure, ground
current (accessory), or low oil pressure, the control module
locks the unit off and must be manually reset (turn the ON-
OFF switch to OFF and then back to ON). If the unit trips
out on low fluid temperature, chilled fluid flow switch, or
chilled fluid pump switch, it restarts automatically when the
condition is corrected.
30HW UNITS — Close the compressor circuit breaker and
move ON-OFF switch to the ON position. The switch should
light up. In approximately 3 seconds, the compressor starts
unloading. For 2 minutes the low-pressure switch is
bypassed and the unloaders are energized (compressor un-
loads when compressor unloader solenoid is energized). At
end of 2-minute bypass period, the low-pressure switch ac-
tivates the control circuit and the temperature controller regu-
lates the capacity steps based on leaving cooler fluid tem-
perature, set point and deadband settings on the temperature
controller.
If system load drops to the point where the unit is fully
unloaded and the fluid temperature is below the lower dead-
band limit, the compressor shuts off and is not able to restart
until the 5-minute anti-short cycle has expired. If during nor-
mal operation, the fluid temperature rises above the upper
deadband limit, the temperature controller adds a step of ca-
pacity (assuming a step is left to be added).
On condenserless units (30HWA), or on fluid-cooled units
(30HWB,C, and S) equipped with the accessory oil safety
switch, the control module provides a 2-minute bypass of
the oil safety switch.
If the unit is equipped with hot gas bypass option, the hot
gas bypass valve closes before unloaders are deactivated.
If the unit trips out on high pressure, ground current (ac-
cessory), or low oil pressure, the control module locks the
unit off and must be manually reset (by turning the ON-OFF
switch to OFF, then back to ON). If the unit trips out on low
pressure, low fluid temperature, the chilled fluid flow switch,
or the chilled fluid pump switch, it restarts automatically when
the condition is corrected.
Table 10 — Capacity Control Steps — 30HK, HL Standard Units
UNIT
CONTROL
STEPS
TRANSFER SWITCH COMPRESSOR
NO. 1 POSITION*
TRANSFER SWITCH COMPRESSOR
NO. 2 POSITION*
%
Disp.
Operating Cylinder
%
Disp.
Operating Cylinder
Total Ckt 1 Ckt 2 Total Ckt 1 Ckt 2
30HK040
1 25 2 2 — 25 2 — 2
2 50 4 2 2 50 4 2 2
3 75 6 4 2 75 6 2 4
4 100 8 4 4 100 8 4 4
30HK,HL050
1 40 4 4 — 20 2 — 2
2 60 6 4 2 60 6 4 2
3 80 8 6 2 80 8 4 4
4 100 10 6 4 100 10 6 4
30HK,HL060
1 33 4 4 — 33 4 — 4
2 66 8 4 4 66 8 4 4
3 8810 6 4 8810 4 6
4 100 12 6 6 100 12 6 6
LEGEND
Ckt — Circuit
Disp. — Displacement
*Manually operated.
NOTE: Circuits are designated from left to right when viewed from
front of unit.
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