HVACopediaNTI · Boiler
Alert 448 Flame too low - burner shut down
What the control is telling you
Burner had to shut off because the flame signal was too weak.
Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399
Likely causes
- Blocked venting
- Dirty heat exchanger
- Failing flame sensor
- Poor combustion settings
Test and repair steps
- If the alert keeps coming back, work through the Lockout 138 checks
Models that show this code
13 models in Trinity Tft
Other codes on the same units
- Alert 43 IAS start check was forced on due to IAS enabled
- Alert 43 IAS start check was forced on due to IAS enabled
- Alert 44 Low voltage was detected in safety processor
- Alert 44 Low voltage was detected in safety processor
- Alert 449 Modulation limited by flame strength
- Alert 449 Modulation limited by flame strength
- Alert 45 High line frequency occurred
- Alert 45 High line frequency occurred
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Source: NTI Trinity Tft399 Installation and Operation Manual (2018-09-07), Sec. 16.0 Troubleshooting, Table 16-4. 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.