E53

Suction Pipe Thermistor (Tho-S) Disconnected

Mitsubishi Electric · Mitsubishi FR-D700 Inverter

What does E53 mean?

The suction pipe thermistor (Tho-S) is disconnected, which will prevent accurate temperature readings for the suction line. This compromises the system's ability to regulate superheat and optimize refrigerant flow.

Additional Steps

Steps 1–2 are listed in Priority Fix.

  1. 3

    Ensure the thermistor is correctly seated and secured on the suction pipe, making good thermal contact.

Source: Mitsubishi FR-D700 Inverter
Open Manual (Page 5)