HVACopediaNTI · Boiler
Alert 491 Internal error: Safety key bit 13 was incorrect
What the control is telling you
Control board logged an internal error: Safety key bit 13 was incorrect.
Applies to: Trinity Tft60, Tft85, Tft110, Tft155, Tft175, Tft200, Tft250, Tft300, Tft399
Models that show this code
13 models in Trinity Tft
Other codes on the same units
- Alert 489 Internal error: Safety key bit 11 was incorrect
- Alert 49 Maximum cycle count was reached
- Alert 49 Maximum cycle count was reached
- Alert 490 Internal error: Safety key bit 12 was incorrect
- Alert 492 Internal error: Safety key bit 14 was incorrect
- Alert 493 Internal error: Safety key bit 15 was incorrect
- Alert 494 Internal error: Safety relay timeout
- Alert 495 Internal error: Safety relay commanded off
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Source: NTI Tft60-399 Installation and Operation Instructions (rev. 2012-04-09), Sec. 15.0 Troubleshooting, Table 15-4. 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.