NTI Boiler: No power – checking 120 VAC and 24 VAC at the boiler
No power - checking 120 VAC and 24 VAC at the boiler on a NTI boiler: Nothing on the display or no response to a heat call; confirm the power supplies first.
Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399
Common causes of no power - checking 120 vac and 24 vac at the boiler
- Breaker tripped or service switch off
- Front-of-boiler service switch off
- No call from thermostat
- Blown fuse (120 VAC fuse or 24 VAC fuse C)
How to fix no power - checking 120 vac and 24 vac at the boiler: step by step
- Confirm the breaker, any service switch and the switch on the front of the boiler are on
- Confirm the thermostat is calling and has 24 VAC
- Remove the front cover, then the control panel cover (three #8 screws)
- Measure 120 VAC across L1 and L2 (terminals 1 and 5); if absent trace the supply wiring
- If 120 VAC is there, shut power off and check the 120 VAC fuse on the control panel
- Measure 24 VAC between R and COM (terminals 1 and 2); if absent check the 24 VAC fuse at the transformer
If the unit shows an error code, look it up: NTI Boiler codes
Models
Tft60Tft60Tft85Tft85Tft110Tft110Tft154Tft155Tft175Tft200Tft201Tft250Tft285Tft300Tft340Tft399Tft399
Source: NTI Trinity Tft399 Installation and Operation Manual (2018-09-07), Sec. 16.0 Troubleshooting. 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.