HVACopediaNTI · Boiler
Alert 206 Lead-lag header temperature invalid
What the control is telling you
No usable system (header) sensor reading.
Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399
Likely causes
- System sensor not connected
Test and repair steps
- Fit a system sensor on the SYSTEM and COM sensor terminals if you want one, otherwise ignore this alert
Models that show this code
13 models in Trinity Tft
Other codes on the same units
- Alert 20 Backdoor password could not be determined
- Alert 204 Lead Lag master was suspended due to fault
- Alert 205 Lead Lag slave was suspended due to fault
- Alert 206 Lead-lag header temperature invalid
- Alert 207 Lead Lag was suspended due to no enabled Program Module installed
- Alert 208 Lead Lag slave session has timed out
- Alert 21 Invalid safety group verification table was not accepted
- Alert 22 CRC errors were found in application configuration data blocks
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.
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.