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Laura MorrisonSep 8, 2025
How to troubleshoot Fault Code E03 System Sensor Failure on my HTP Boiler?
- CcdavenportSep 9, 2025
If your HTP Boiler displays Fault Code E03, it means there's a system sensor failure, possibly due to an open or shorted circuit. Here’s how to troubleshoot: Disconnect the system sensor from the wiring and measure its resistance. Compare the measured resistance to the table to see if it corresponds to the sensor's temperature. If the resistance doesn't match, replace the sensor. If the sensor is OK, disconnect the sensor wiring from both the boiler and the sensor, then check continuity using an ohmmeter. Repair or replace the wiring as necessary.





