62-110394-17
6. HIGH EVAPORATOR PRESSURE
UL2 will always be energized (unloaded) when the suction pressure reaches the value shown in the chart below,
according to the current ambient temperature. For example, at an ambient temperature of 100°F, UL2 will be
energized when the suction pressure rises to approximately 75 psig (5 Bar).
0
20
40
60
80
100
90 100 110 120 130 140
Ambient Temperature
PSIG
Figure 4--6.Evaporator Pressure Chart
7. HIGH DISCHARGE PRESSURE
• When the compressor discharge pressure reaches
435 psig (30 Bar) for more than 1 minute, UL2 will
energize (unload). UL2 will remain energized until the
compressor discharge pressure drops below 415 psig.
• If both UL1 and UL2 are energized (unloaded), and
the discharge pressure drops below 415 psig (28.2 Bar),
UL1 will be de--energized (loaded).
8. LOW SUCTION PRESSURE
• If suction pressure falls below 4” Hg (vacuum) for
more than 20 seconds, energize (unload) UL2.
• Once the suction pressure rises above 5 psig,
de--energize (load) UL2 (after the 2--Minute Delay
mentioned above.) OR…
• After 20 seconds: if suction pressure is still less than
4” Hg, energize (unload) UL1.
• If both UL2 and UL1 are energized (unloaded) AND
20 seconds has elapsed since energizing (unloading)
UL1 AND the suction pressure rises above 5 psig,
de--energize (load) UL1.
9. HIGH CDT
If the compressor is operating with both UL1 and
UL2 energized (unloaded), and the CDT rises to 285°F
(140°C), UL1 will be de--energized (loaded), and will
remain de--energized until the CDT drops below 265°F
(130°C) for at least 2 minutes.
10.DEFAULT MODE
Refer to Section 4.4.9
11.START--STOP WITH A FROZEN SETPOINT
In Start/Stop Mode, when any compartment
setpoint is in the frozen range, and the minimum run
time has expired, and the box temperature is not at
setpoint, both UL1 and UL2 will be de--energized and
the compressor will operate on 6--cylinders.
12.HIGH SPEED PULLDOWN
When only Compartment 1 is enabled, and the
setpoint for Compartment 1 is in the perishable range,
and the unit is operating in Continuous Run, and the
High Speed Pulldown configuration is set for YES, then
the compressor will operate with both unloaders
de--energized (6--cylinder operation) until the box
temperature is within +/-- 0.4°F (0.2C) of setpoint.
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