7 known error codes for this model

11 Call a Pro

Ignition failure: unit could not light burner.

12 Call a Pro

Flame loss after ignition (weak or unstable flame).

16 Moderate

Abnormally high outlet water temperature detected.

20 Call a Pro

High-limit safety switch was triggered.

29 Moderate

Condensate drainage problem detected.

45 Call a Pro

Water leak detected internally by leak sensor.

71 Call a Pro

Gas solenoid valve drive circuit abnormality.