HVACopediaLennox · Air handler
507 PureAir filter calibration failure
What the control is telling you
Filter calibration failed: all test CFM static pressures read 7 Pa or less; no filter tests or life calculation while active. S30/S40 thermostat alert code 507.
Applies to: Lennox communicating air handlers and EIM-equipped indoor units in S30/S40 smart thermostat systems
Likely causes
- PureAir S accessory issue
Test and repair steps
- Check the filter is installed and pressure tubing connected.
- Replace and reset the filter.
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Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.44. Summarized in our own words; check the original manual for your model.
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