Thermal Solutions APEX APX425C User Manual

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106308-05 - 3/23
APEX Installation, Operating, & Service Instructions
Lockout
Number
Condition Possible Cause
15
Return
Temperature
Higher Than
Supply
Return temperature was greater
than supply temperature for at least
75 seconds.
• 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
16
Supply
Temperature
Risen Too Quickly
Supply water temperature has risen
too quickly.
• Inadequate boiler water flow. See also causes for Hard Lockout 4.
• Boiler pump not operating
• Boiler pump undersized
• Valve closed
18
Light-off Rate
Proving Failed
Blower not running at requested
light-off rate or blower speed signal
not detected
• Loose connection in 120 VAC blower wiring
• Loose or miswired blower speed harness
• Defective blower
19
Purge Rate
Proving Failed
Blower not running at requested
purge rate or blower speed signal
not detected
• Loose connection in 120 VAC blower wiring
• Loose or miswired blower speed harness
• Defective blower
20
Configuration
Fault
Unacceptable control safety
parameter detected. See display
for details.
Safety parameter verification required. Contact factory.
21
Invalid
Modulation
Parameters
Unacceptable control modulation
parameter detected.
Reset control. If problem persists, contact factory.
22
Safety Data
Verification
Needed
Safety parameter change detected
and verification has not been
completed.
• Safety related control parameter has been changed and
verification
has not been performed.
• Control not programmed. Contact factory.
23
24 VAC Voltage
Low/High
Control 24 VAC control power is
high or low.
• 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.
24
Fuel Valve Error
Power detected at fuel valve output
when fuel valve should be off.
• 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.
25
Hardware Fault
Internal control failure.
See display for details.
Reset control. If problem recurs, replace control.
26
Internal Fault
Internal control failure. Reset control. If problem recurs, replace control.
27
Ignition Failure
Flame not detected at end of
ignition sequence.
• 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.
Table 12-5: Hard Lockout Codes (continued)
12 Troubleshooting (continued)

Thermal Solutions APEX APX425C Specifications

General

Brand	Thermal Solutions
Model	APEX APX425C
Category	Boiler
Language	English