Error E53 / Outdoor Red LED Flashes Once — Suction pipe thermistor or low pressure sensor fault

What does E53 / Outdoor Red LED 1 flash mean?

Error E53, indicated by one flash of the outdoor unit's red LED, points to a disconnected suction pipe thermistor (Tho-S) or a disconnected/output error with the low pressure sensor (PSL). Both are critical for system monitoring.

• Suction pipe thermistor (Tho-S) disconnected
• Low pressure sensor (PSL) disconnected/output error

Click steps to track your progress.

1. 1

   Turn off the main power to the outdoor unit.

2. 2

   Inspect the connections of both the suction pipe thermistor (Tho-S) and the low pressure sensor (PSL) to the outdoor PCB.

3. 3

   Ensure all connectors are firmly seated and free from corrosion or damage.

4. 4

   Gently reseat the connectors if they appear loose.

5. 5

   If the error persists after checking connections, these sensors may need replacement by a professional technician.