Carrier VECTOR 6500 Operation & Service Manual page 187

Alarm
Steps
NO.
85 CHECK UL1 CIRCUIT
•
TRIGGER–ON: Front Unloader (UL1) circuit is shorted. (The UL1 output from the microprocessor
(3MP12) is negative, so the circuit will not be shorted to ground, but is shorted either within UL1
itself, or to a positive wire.)
•
UNIT CONTROL: Engine and Standby Operation: alarm only.
•
RESET CONDITION: Auto Reset when the UL1 Coil current (amp) draw is normal, 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 Front Unloader (UL1) Coil
a. Inspect Front Unloader (UL1) coil
& connector.
b. Check resistance of coil
c. Check amp draw of coil.
2 Check Front Unloader (UL1) Current Draw
Use Component Test Mode to test
actual current draw of the circuit.
(Refer to Section 5.2.2.)
3 Check Front Unloader (UL1) Coil Wiring
Inspect harness & control box con-
nector pins & terminals. (See wiring
schematic Section 10.)
62-11389
Alarm/Cause
7−54
Corrective Action
No damage to coil
No damage, moisture, or corrosion in connector.
Refer to Section 2.12 for correct electrical values.
Cannot be opened (infinite ohms), shorted (Zero
Ohms) or shorted to ground.
Refer to Section 2.12 for correct electrical values.
Use ammeter.
Refer to Section 2.12 for correct electrical values.
View current draw in Data List.
No physical damage to harness.
No damage, moisture, or corrosion in connectors.