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NTI · Boiler troubleshooting

Display is blank

Trinity Tft

What is going on

Touchscreen shows nothing. The display may just have timed out and blanked itself, so touch it first.

Likely causes

  • Screen timed out
  • Blown fuse C (often from a short in thermostat wiring)
  • 24 VAC missing at display plug
  • Display wiring loose

Check in this order

  1. Touch the screen to wake it and confirm the service switch under the display is on
  2. Remove the control panel cover and check fuse C; if blown, look for shorts in the thermostat wiring first
  3. Check the 2 by 2 Molex connector behind the top of the display; measure 24 VAC between the blue and red wires and trace back to the transformer if missing
  4. Remove the display assembly and check blue to terminal 7 (24VAC COM) and red to terminal 8 (24VAC)

Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399

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Source: NTI Trinity Tft399 Installation and Operation Manual (2018-09-07), Sec. 16.0 Troubleshooting. Written in our own words; check the manual for your exact model.

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.