HVACopediaNTI · Boiler
Hold / Lockout 88 Outlet temperature rise limit
What the control is telling you
Water temperature rise across the boiler exceeded the allowed rise.
Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399
Likely causes
- Insufficient water flow
Test and repair steps
- Follow the Lockout 81 checks fuse B, boiler pump, piping, 15 PSI minimum pressure, scale
Models that show this code
13 models in Trinity Tft
Other codes on the same units
- Hold / Lockout 81 Delta T limit
- Hold / Lockout 85 Inlet/outlet inversion limit
- Hold / Lockout 85 Inlet/outlet inversion limit
- Hold / Lockout 88 Outlet temperature rise limit
- Hold / Lockout 9 Flame bias out of range
- Hold / Lockout 9 Flame bias out of range
- Hold 100 Pressure sensor fault
- Hold 100 Pressure sensor fault
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Source: NTI Trinity Tft399 Installation and Operation Manual (2018-09-07), Sec. 16.0 Troubleshooting, Table 16-3. Summarized in our own words; check the original manual for your model.
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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.