5-7
TROUBLESHOOTING
DC SERIES BOILERS / WATER HEATERS DC 15-95, DC 15-96, DC 20-125, DC 33-160
5.3.2 Fault codes
If the fault LED is ashing, the controller has detected a fault. A fault code will be displayed on the main display. Once
the fault has been corrected the burner controller can be restarted. Press the Reset button on the operating panel
to restart the burner controller.
MAIN DISPLAY DISPLAY FAULT POSSIBLE SOLUTION
10, 11, 12, 13, 14 Sensor fault S1
Supply Sensor (upper left side of
the heat exchanger)
• See below, 1 – Temperature too high
• Check the positioning of S1
• Check wiring for break
• Replace S1
20, 21, 22, 23, 24 Sensor fault S2
Return Sensor (lower left side of
the heat exchanger)
• Check the positioning of S2
• Check wiring for break
• Replace S2
0 Sensor fault after self check Replace S1 and/or S2
1 Temperature too high
• Air in system. Bleed the system of any remaining air
• Pump not running, bleed air from and/or replace the pump
• Insufcient ow in installation, radiators closed
2 S1 and S2 interchanged
• Check wiring harness
• Replace S1 or S2
4 No ame signal
• Gas valve closed
• Gas supply pressure too low or drooping under load
• Gas valve or ignition unit not powered
• No or incorrect ignition gap
• Condensate drain blocked
• Check grounding of all parts
5 Poor ame signal
• Condensate drain blocked
• Gas supply pressure too low or drooping under load
• Check ignitor and ignition cable
• Check gas valve adjustment
• Check grounding of all parts of the installation
• Check combustion air supply and ue gas exhaust piping and
terminations, possible ue gas recirculation in the system
6 Flame detection fault
• Replace ignition cable + ignitor cap
• Replace ignition module
• Replace controller
8 Incorrect fan speed
• Fan rubbing on casing
• Wiring between fan and casing
• Check wiring for poor wire contact
• Replace fan
• Replace controller
18 Flue Gas Temperature Sensor
Open – Lockout Condition
• Inspect heat exchanger for fouling and clean as required
• Check wiring
• Replace Sensor
19 Flue Gas Temperature Sensor
Short – Lockout Condition
• Inspect heat exchanger for fouling and clean as required
• Check wiring
• Replace Sensor
29,30 Gas valve relay faulty Replace controller