62-11389
7
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7
Alarm
NO.
Steps
Alarm/Cause
Corrective Action
13
HIGH DISCHARGE PRESSURE (ALARM 75 WILL ALSO ACTIVATE)
•
TRIGGER–ON: Compressor discharge pressure switch (HP1) contacts are open. HP1 contacts
open when the discharge pressure rises to 465 psig (31.6 bar.)
•
UNIT CONTROL:
Engine Operation: Engine and unit shutdown and alarm.
Standby Operation: Refrigeration system shutdown and alarm with PSCON
still energized.
•
RESET CONDITION: Auto Reset after 15 minutes if the compressor discharge pressure falls below
350 psig (23.8 bar), or alarm may be manually reset via keypad or by turning the unit off,
then back on again.
NOTE: Follow the steps below until a problem is found. Once a repair or correction has been made, the active
alarm should clear itself (see reset condition above). Operate the unit through the appropriate modes to see if
any active alarm occurs. Continue with the steps below as necessary.
1
Check System Pressures
Install manifold gauge set and check
and compare compressor discharge
& suction pressures with those
shown on the microprocessor.
Suction & Discharge Pressures must have the same
reading on gauges & on microprocessor display.
Pressures must be in the normal range for ambient &
refrigerated compartment temperature conditions. If
discharge pressure is in normal range, proceed to
step 4.
NOTE: Microprocessor suction (CSP) and evaporator
(EVOP) pressure readings have a maximum value of
100 psig (7.5 bar) The actual suction pressure must
be lower than 100 psig in order to perform this test.
2
Check Airflow Through Condenser Coil
a. Inspect condenser & radiator.
Ninety percent or more of the coil surface must be
undamaged. Condenser coil and radiator must be
clean.
b. Check airflow (with unit running.)
Even airflow through the entire coil.
No “dead” spots.
c. Check condenser fans.
Both fans should operate correctly. Check rotation,
air should be pulled in through the grill, and discharge
into the engine compartment.
3
Check For Refrigerant Overcharge
Check refrigerant charge.
Refer to Section 8.6.2.
4
Check HP1 Switch
Inspect switch & connector pins &
terminals.
No physical damage to switch.
No damage, moisture, or corrosion in connector.
5
Check HP1 Switch Harness
a. Inspect harness & control box
connector pins & terminals. (See
wiring schematic Section 10.)
No physical damage to harness.
No damage, moisture, or corrosion in connectors.
b. Check for shorted circuit in harness,
and continuity through the harness.
Energize Circuit. (See Note 2, page 7
−
2.) Check for
voltage from SP5, through switch and SP15 to micro-
processor terminal 2MP29.
6
Check HP1 Switch
Check switch operation.
Test switch, refer to Section 8.8.7 step b.
