NTI · Boiler

4 31 Code 431 (no description printed)

Menu / mode display TRX

What the display is showing

Code 431 appears in the table with no description or remedy printed on these pages. Refer to the full manual or the manufacturer.

Applies to: TRX150

Models that show this code

5 models in TRX

TRX085TRX110CTRX150TRX199TRX199C

Other codes on the same units

4 11 Room sensor open or short circuit, Zone 1
4 12 Room sensor open or short circuit, Zone 2
4 13 Room sensor open or short circuit, Zone 3
4 30 Detected accessory wired to BUS connection
05 01 Ignition lockout after 3 failed attempts
05 02 Flame detected with gas valve closed
05 04 10 flame lifts in one operating cycle
5 P1 1st ignition failed

Save it for the next call

Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.

Open the app

Source: NTI TRX150 manual, p. 91. Summarized in our own words; check the original manual for your model.

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.