HVACopediaNTI · Boiler
Alert 248 CH outdoor temperature invalid
What the control is telling you
No usable outdoor sensor reading for central heat. Outdoor reset is enabled from the factory, so the control expects the sensor.
Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399
Likely causes
- Outdoor sensor not connected
- Outdoor sensor wiring fault
- Faulty sensor
Test and repair steps
- Connect the outdoor sensor, or turn outdoor reset off
- Verify the sensor wires land on OUTDOOR and COM in the sensor terminal strip
- Keep the sensor clear of ice and snow, and compare its resistance to the thermistor chart
Models that show this code
13 models in Trinity Tft
Other codes on the same units
- Alert 240 LL water temperature range was too small (minimum 12 C / 22 F)
- Alert 246 CH set point was invalid
- Alert 247 CH time of day set point was invalid
- Alert 248 CH outdoor temperature invalid
- Alert 249 CH ODR time of day setpoint was invalid
- Alert 25 Lead Lag operation switch was turned OFF
- Alert 250 CH ODR time of day set point exceeds normal set point
- Alert 251 CH max outdoor set point was invalid
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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.
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