PH90 — High temperature protection of Evaporator

What does PH90 mean?

The evaporator coil has reached a high temperature, activating a protection mechanism. This is more common in heating mode.

• Restricted airflow over the evaporator coil
• Low refrigerant charge
• Improper system operation (e.g., heating mode when it shouldn't be)
• Dirty air filter

Click steps to track your progress.

1. 1

   Ensure the air filter for the indoor unit is clean.

2. 2

   Check that the indoor unit's air inlet and outlet are not blocked.

3. 3

   Verify the system is set to the correct mode (cooling/heating).

4. 4

   If the problem persists, a technician should check refrigerant levels and airflow.