Low Pressure Protection (Refrigerant Shortage)

What it means

This code appears on Gree split air conditioners when the system detects low suction pressure or signs of refrigerant shortage, and it stops the compressor to protect it from running without proper cooling. Detection differs between Gree series: some use a low-pressure switch, others rely on temperature readings, so check the unit manual. The same code can mean something else on other brands.

Models covered: Gree split (wall-mounted) air conditioners, mainly inverter models; the code shows on the indoor unit display. Older non-inverter models may show fewer codes.

Related codes: E1E4E2H3

Symptoms4

• Weak or no cooling before the code appears.
• Frost on the small pipe or the service valve at the outdoor unit.
• The compressor stops soon after starting.
• Oil traces around joints or service valves in some cases.

Possible causes5

• Refrigerant leak at flare joints, the evaporator or the condenser, which is the most common cause.
• Outdoor service valves not fully opened after installation.
• Factory charge too low for a long pipe run with no extra refrigerant added.
• Blocked capillary tube, electronic expansion valve or strainer.
• Faulty low-pressure switch or wiring on models that have one.

How to diagnose5

1. Switch off at the breaker and restart once only; do not keep resetting if the code returns.
2. Look for oil traces at the joints under the indoor unit and at the outdoor unit.
3. The technician confirms the service valves are fully open.
4. The technician measures suction pressure against the manufacturer chart, then leak-tests with nitrogen or an electronic detector.
5. If pressure is normal, the technician checks the low-pressure switch, its wiring and the expansion valve.

How to fix5

1. Fully open the service valves if they are partly closed.
2. Retighten or re-flare a leaking flare joint.
3. Braze the leak in the evaporator or condenser, then vacuum the circuit and charge refrigerant by weight.
4. Replace a blocked expansion valve or strainer, or the pressure switch, as tested.
5. Run the unit, check pressures and pipe temperatures, and confirm the code is gone.

A service valve or flare joint is cheap to fix; brazing a coil leak and a full recharge costs more. Refrigerant work is for a licensed technician only.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions