The flame rod detects flame via micro-current. Carbon and oxidation buildup degrades the signal. The most-replaced Takagi part, behind a large fraction of Code 111 and Code 112 faults on units 5+ years old.
Symptoms
- Intermittent Code 112
- Persistent Code 111 on older units
- Unit takes multiple attempts to light
- Burner cycles on/off during a single draw
Clean first (free)
- Power off and shut off gas
- Remove front cover
- Locate flame rod — small metal probe in burner area
- Unscrew or unplug
- Clean with fine sandpaper (400-grit). Polish until bright metal
- Reinstall, close, power on, test
Cleaning resolves about 60% of cases on units 5+ years old.
Replace if cleaning doesn't work
Cost: $25-70 OEM.
Bottom line
Before calling anyone about Code 111 or 112, clean the flame rod. Free, 20 minutes, most common fix.