HVACopediaNTI · Boiler
02 09 Storage overheating
What the control is telling you
Turns on above 176 °F and off below 175 °F. CH demand continues to run.
Applies to: TRX150
Likely causes
- Damaged tank sensor or wiring
Test and repair steps
- Check the tank sensor and its wiring.
- Replace the tank sensor if it is damaged.
Models that show this code
5 models in TRX
Other codes on the same units
- 1 P3 Inadequate circulation or missing water (warning)
- 02 01 Damaged or shorted DHW temperature probe
- 02 03 Storage temperature probe open or short circuit
- 02 05 DHW inlet probe open circuit
- 2 P2 Anti-Legionella function not completely finished
- 03 01 Display EEPROM error
- 03 02 Communication error GP-GIU
- 03 03 PCB internal error
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Source: NTI TRX150 manual, p. 91. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.