Error 42 — High pressure switch circuit is open

What does [42] Open high pressure switch mean?

The high pressure switch circuit has been detected as open for 30 seconds after the compressor has been running for 3 minutes. If this error occurs 3 times within an hour, it will lock the system.

• Incorrect pressure switch wiring
• Abnormal system pressure
• System is clogged
• Incorrect refrigerant charge
• Faulty valve
• Faulty pressure switch
• Faulty PCB

Click steps to track your progress.

1. 1

   Check if the pressure switch wiring connection is okay.

2. 2

   Use a multimeter to check if the high pressure switch terminal is short-circuited.

3. 3

   Ensure the Electronic Expansion Valve (EEV) coil is fully seated.

4. 4

   Check if the service valve is open.

5. 5

   Short the high pressure switch terminal on the PCB to see if the system reports a failure.

6. 6

   Check if the piping system is clogged.