00086 Check Ul2 Circuit - Carrier X4 7300 Operation & Service Manual

00086 CHECK UL2 CIRCUIT
• ACTIVATION: A problem has been detected in the front unloader (UL2) coil circuit. If this alarm is activated
while the control system is calling for UL2 to be energized, the circuit is detected shorted. If this alarm
occurs at any other time, the circuit is detected open.
• UNIT CONTROL: Alarm only.
• RESET CONDITION: Auto reset when the circuit is normal, or Alarm may be manually reset using the dis-
play mounted keys 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.
CORRECTIVE ACTIONS:
1. Check for Additional Alarms
If this alarm is activated in conjunction with other alarms (00031, 00041 00071, 00072, 00078, 00079,
00080 or 00085) check F5 & F10. Fuses must be good. Replace fuse(s) as required, clear alarms,
restart and check for repeat alarm(s).
2. Check Coil
a. Inspect coil & connector pins & terminals. Verify no damage to coil. Verify no damaged or corroded
pins.
b. Check resistance of coil. Refer to
c. Use Component Test Mode (Refer to
Section 2.10
3. Check Power and Wiring
a. Use Component Test Mode (Refer to
nal A and 3MM-8. Minimum 11 VDC. If not, check connectors and wiring between terminals. Verify no
damage, moisture or corrosion.
b. Check for ground at UL2 terminal B (including SP-2) to GND1RING2. Good ground. If not, check con-
nectors and wiring between terminals. Verify no damage, moisture or corrosion.
62-11637
Section 2.10
Section
for specifications. Verify that the actual current is within specifications.
Section
for specifications.
5.2.4) to test actual current draw of the circuit. Refer to
5.2.4) to energize circuit. Check for power at UL2 termi-
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