HVACopediaNTI · Boiler troubleshooting
Low water cutoff / ILK OFF lockout (67)
What is going on
Burner will not fire and display reads ILK OFF.
Likely causes
- Low water in boiler
- External limit open
- Condensate blockage switch open
Check in this order
- Check water level and the internal low water cutoff
- Check any external limit wired between R and LIM
- Clean the condensate trap and drain and check the vent, then clear the lockout; if still open, test the condensate switch contacts 1 and 2 for continuity
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.