Tosot Indoor Coil Low Temperature Protection in Heating

Indoor unit shows H9, poor heating performance

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Low outdoor temperature with insufficient capacity, Low refrigerant charge, Indoor coil sensor misreading, Restricted indoor airflow

Safety first: Turn off power before cleaning.

Clean filters and coil: Ensure indoor airflow is not restricted.
Check sensor placement: Verify the indoor coil sensor is properly attached.
Observe operation: In very cold weather, H9 may indicate the unit is protecting itself. Supplementary heat may be needed.
If frequent H9 in mild weather: Have a technician check refrigerant charge and system performance.

Medium 3/5

Indoor Coil Temperature Sensor

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