Ducane 4AC16LT Series - Page 16

Page 16 of 19 506467-01Issue 1946
LED Status Fault Description Troubleshooting Information
ALERT
(Yellow)
Flash Code 7
Open Run Circuit
Current only in start circuit
1. Open circuit in compressor run wiring or connections
• Check wiring and connectors between supply and the compressor R terminal
2. Compressor run winding is damaged
• Check compressor motor winding resistance
ALERT
(Yellow)
Flash Code 8
Welded Contactor
Compressor always runs
1. Compressor contactor has failed closed
2. Thermostat demand signal not connected to module
ALERT
(Yellow)
Flash Code 9
Low Voltage
Control circuit less than
17VAC
1. Control circuit transformer is overloaded
2. Low line voltage (contact utility if voltage at disconnect is low)
• Check wiring conditions
Table 5. Diagnostic Module Codes
Mis-wired Module Indication Recommended Troubleshooting Action
Green LED is not on; module
does not power up
Determine if both R and C module terminals are connected. Verify voltage is present at module’s R
and C terminals. Review 24VAC Power Wiring section for R and C wiring.
Green LED intermittent;
module powers up only when
compressor runs.
Determine if R and Y terminals are wired in reverse. Verify module’s R and C terminals have a
constant source. Review 24VAC Power Wiring section for R and C wiring.
TRIP LED is on, but system
and compressor check OK.
Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coils falls below
0.5VAC when o󰀨.
TRIP LED and ALERT LED
ashing together.
Verify R and C terminals are supplied with 19-28VAC.
ALERT Flash Code 3
(compressor short cycling)
displayed incorrectly.
Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below
0.5VAC when o󰀨.
ALERT Flash Code 5, 6, or 7
(open circuit, open start circuit,
or open run circuit) displayed
incorrectly.
Check that compressor run and start wires are through module’s current sensing holes. Verify Y
terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below 0.5VAC
when o󰀨.
ALERT Flash Code 6 (open
start circuit) displayed for
Code 7 (open run circuit) or
vice versa.
Check that compressor run and start wires are routed through the correct module sensing holes.
ALERT Flash Code 8
(welded contactor) displayed
incorrectly.
Determine if module’s Y terminal is connected. Verify Y terminal is connected to 24VAC at contactor
coil. Verify 24 VAC is present across Y and C when the thermostat demand signal is present. If not,
R and C are reverse wired. Verify voltage at contactor coil falls below 0.5VAC when o󰀨. Review
Thermostat Demand Wiring for Y and C wiring.
Table 6. Mis-wired Module Troubleshooting