Thermal Solutions APEX APX425C Installation, Operating And Service Instructions page 126

12
Troubleshooting
Table 12-5: Hard Lockout Codes (continued)
Lockout
Number
15
Return Return temperature was greater
Temperature than supply temperature for at least
Higher Than
Supply
16
Supply Supply water temperature has risen
Temperature
Risen Too Quickly
18 Blower not running at requested
Light-off Rate light-off rate or blower speed signal
Proving Failed
19 Blower not running at requested
Purge Rate purge rate or blower speed signal
Proving Failed
20 Unacceptable control safety
Configuration parameter detected. See display
Fault
21
Invalid Unacceptable control modulation
Modulation
Parameters
22
Safety parameter change detected
Safety Data
and verification has not been
Verification
Needed
23
Control 24 VAC control power is
24 VAC Voltage
Low/High
24 Power detected at fuel valve output
Fuel Valve Error when fuel valve should be off.
25
Hardware Fault
26
Internal Fault
27 Flame not detected at end of
Ignition Failure
126
(continued)
Condition
75 seconds.
too quickly.
not detected
not detected
for details.
parameter detected.
completed.
high or low.
Internal control failure.
See display for details.
Internal control failure.
ignition sequence.
APEX Installation, Operating, & Service Instructions
Possible Cause
• Reversed flow through boiler. Verify correct piping and circulator
orientation.
• No boiler water flow. Verify system is purged of air and
appropriate
valves are open.
• Defective supply or return sensor
• Inadequate boiler water flow. See also causes for Hard Lockout 4.
• Boiler pump not operating
• Boiler pump undersized
• Valve closed
• Loose connection in 120 VAC blower wiring
• Loose or miswired blower speed harness
• Defective blower
• Loose connection in 120 VAC blower wiring
• Loose or miswired blower speed harness
• Defective blower
Safety parameter verification required. Contact factory.
Reset control. If problem persists, contact factory.
• Safety related control parameter has been changed and
verification
has not been performed.
• Control not programmed. Contact factory.
• Loose connection in 24 VAC power wiring.
• Loose or miswired 24 VAC harness.
• Miswired wiring harness causing power supply short to
ground.
• Defective transformer.
• Transformer frequency, voltage and VA do not meet
specifications.
• Loose or defective gas valve harness. Check electrical
connections.
• Defective gas valve. Before replacing valve, check for 24 VAC at
gas valve connector during trial for ignition.
Reset control. If problem recurs, replace control.
Reset control. If problem recurs, replace control.
• Gas line not completely purged of air.
• Gas pressure too low. See minimum on boiler rating label.
• Air-fuel mixture out of adjustment. See System Start-Up Section.
• Disconnected or defective igniter wire.
• Disconnected or defective flame sensor wire.
• Defective igniter electrode.
• Defective flame sensor.
• Defective gas valve. Before replacing valve, check for 24
VAC at gas valve connector during trial for ignition.
106308-05 - 3/23