What It Means
- MMD***M6-1P: Error indicating a refrigerant leak sensor replacement is required
- MMD***S6-1P: R-32 detection sensor replacement alarm
Lennox Air handler
Lennox Error Code 699
Air handler
699 means different things on different Air handler models. Enter your model number to see only your reading, or find your model below.
Causes & actions from Lennox
Error indicating a refrigerant leak sensor replacement is required
Models: MMD***M6-1P
Air handler (indoor)
How it shows
- Wired controller display: 699
This manual entry does not list further causes or actions.
Applicable models & manual sources
- MMD***M6-1P
Error indicating a refrigerant leak sensor replacement is required
R-32 detection sensor replacement alarm
Models: MMD***S6-1P
Air handler (indoor)
How it shows
- Wired controller display: 699
This manual entry does not list further causes or actions.
Applicable models & manual sources
- MMD***S6-1P
R-32 detection sensor replacement alarm
Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.
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