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NTI Error Code 06 02: Exhaust temperature above 204 °F (96 °C) (Boiler)

Updated · by Aurora Star Tech Inc.

NTI error code 06 02 on a boiler means: Exhaust temperature above 204 °F (96 °C). It is also called NTI diagnostic code 06 02.

Critical severityBoilerTRX

Homeowner? What NTI code 06 02 means for you

Stop and call Your boiler is reporting: Exhaust temperature above 204 °F (96 °C). This code is a safety shutdown. Turn the boiler off and call a licensed technician. Do not keep resetting it. If you smell gas, leave the house and call your gas utility or 911 from outside.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does NTI error code 06 02 mean?

Exhaust NTC reads vent temperature above 204 °F. Manual reset.

Applies to: TRX150

Common causes of NTI code 06 02

  • Faulty exhaust sensor
  • Blocked exhaust vent
  • Scaled or dirty heat exchanger

A technician checks these and 1 other possible causes on site before replacing any part.

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

NTI models that use code 06 02

TRX085TRX110CTRX150TRX199TRX199C

Other NTI Boiler codes

CodeMeaning
05 02Flame detected with gas valve closed
05 0410 flame lifts in one operating cycle
5 P11st ignition failed
5 P22nd ignition failed
5 P3Flame loss during run
5 P63rd and 4th ignition failed
06 03APS open
06 05Exhaust NTC circuit open or short circuit
6 12Insufficient fan speed
Alert 1Alert PCB was restored from factory defaults
Alert 2Safety configuration parameters were restored from factory defaults
Alert 3Configuration parameters were restored from factory defaults

All NTI Boiler error codes →

NTI code 06 02: homeowner questions

What does NTI code 06 02 mean?

Exhaust temperature above 204 °F (96 °C). Exhaust NTC reads vent temperature above 204 °F. Manual reset.

Is it safe to keep using my boiler with code 06 02?

No. Code 06 02 is a safety shutdown, so keep the boiler off until a licensed technician has checked it.

Can I reset NTI code 06 02 myself?

Do not keep resetting it. Repeated resets can hide a safety problem; a licensed technician needs to find the cause.

Who can fix NTI code 06 02 near me?

Aurora Star Tech Inc. repairs NTI boilers in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Boiler Not Heating: What to Check

Troubleshooting guides

Source: NTI TRX150 manual, p. 87. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

© 2026 Aurora Star Tech Inc. All rights reserved. This page may not be copied, republished or used to train other systems without written permission.

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