HVACopedia

NTI · Boiler

05 04 10 flame lifts in one operating cycle

High severity TRX

What the control is telling you

Flame lifted off the burner ten times in one cycle. Manual reset.

Applies to: TRX150

Likely causes

  • Gas pressure out of range
  • Faulty gas valve wiring
  • Faulty flame sensor
  • Blocked vent terminations
  • Unstable flame

Test and repair steps

  1. Press Reset to clear the code.
  2. Monitor gas pressure during operation. It should be 3.5 to 10.5 in. WC.
  3. Check the gas valve wire and make sure the connection is secure.
  4. Check the flame detection sensor and its connections. Signal should be more than 2.5 DC before ignition and less than 2.5 DC after ignition.
  5. Check the vent terminations for blockages.
  6. Make sure the flame is stable when lit.
  7. If the problem continues, replace the main control.

Models that show this code

5 models in TRX

TRX085TRX110CTRX150TRX199TRX199C

Other codes on the same units

  • 4 30 Detected accessory wired to BUS connection
  • 4 31 Code 431 (no description printed)
  • 05 01 Ignition lockout after 3 failed attempts
  • 05 02 Flame detected with gas valve closed
  • 5 P1 1st ignition failed
  • 5 P2 2nd ignition failed
  • 5 P3 Flame loss during run
  • 5 P6 3rd and 4th ignition failed

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Source: NTI TRX150 manual, p. 86. Summarized in our own words; check the original manual for your model.

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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.