HVACopedia

NTI · Boiler

6 12 Insufficient fan speed

High severity TRX

What the control is telling you

Fan speed below 500 for 3 seconds, or RPM minimum minus 300 for 3 minutes. Manual reset. Remotely resettable via NTI Tele-Diagnostic Service.

Applies to: TRX150

Likely causes

  • Loose fan connection
  • Faulty fan
  • Faulty control power output

Test and repair steps

  1. Press Reset to clear the code.
  2. Check the fan connections and make sure they are secure.
  3. If the fan does not turn during ignition, check for 8 Vac or 26.5 VDC at the fan connection.
  4. If that power is present at the control, replace the fan. If it is not present at the control, replace the control.
  5. If the problem continues, replace the main control.

Models that show this code

5 models in TRX

TRX085TRX110CTRX150TRX199TRX199C

Other codes on the same units

  • 05 04 10 flame lifts in one operating cycle
  • 5 P1 1st ignition failed
  • 5 P2 2nd ignition failed
  • 5 P3 Flame loss during run
  • 5 P6 3rd and 4th ignition failed
  • 06 02 Exhaust temperature above 204 °F (96 °C)
  • 06 03 APS open
  • 06 05 Exhaust NTC circuit open or short circuit

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Source: NTI TRX150 manual, p. 87. 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.