HVACopediaNTI · Boiler
Alert 121 Modulation commanded rate was > DHW max modulation rate
What the control is telling you
Modulation commanded rate was > DHW max modulation rate.
Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399
Models that show this code
13 models in Trinity Tft
Other codes on the same units
- Alert 12 Annunciation configuration was restored from factory defaults
- Alert 120 Modulation commanded rate was > CH max modulation rate
- Alert 120 Modulation commanded rate was > CH max modulation rate
- Alert 121 Modulation commanded rate was > DHW max modulation rate
- Alert 122 Modulation commanded rate was < min modulation rate
- Alert 122 Modulation commanded rate was < min modulation rate
- Alert 123 Modulation rate was limited due to outlet limit
- Alert 123 Modulation rate was limited due to outlet limit
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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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