1501 — Refrigerant shortage detected

What does 1501 mean?

This code indicates a shortage of refrigerant in the system, or conditions that mimic a shortage. It is detected by specific temperature and pressure readings, such as high discharge superheat and low high-side pressure, especially during heating or cooling operation.

• Refrigerant gas leakage or an insufficient refrigerant charge in the system.
• The outdoor stop valve (ball valve) not being fully open.
• Faulty thermistors (TH3 for outdoor liquid pipe, TH7 for ambient) or the high-pressure sensor (63HS).
• Malfunction of the indoor electronic expansion valve (LEV).

Click steps to track your progress.

1. 1

   Ensure the outdoor stop valve (ball valve) is fully open. This valve controls the refrigerant flow and must be completely open for proper operation.

2. 2

   Check for any visible signs of refrigerant leaks around the outdoor unit, piping connections, or indoor unit (e.g., oily residue).

3. 3

   Turn off the main power to the unit at the circuit breaker, wait for a few minutes, then restore power to reset the system.

4. 4

   If the problem persists, it strongly suggests a refrigerant leak or insufficient charge, which requires a qualified HVAC technician to diagnose, repair, and recharge the system.