How to Manually Adjust an Expansion Valve

The expansion valve is a critical component in automotive and refrigeration air conditioning systems. It regulates the flow of refrigerant into the evaporator, ensuring the correct superheat level for efficient cooling. If your AC is not performing as expected, you may need to manually adjust the expansion valve. This guide explains how to do it safely and effectively.

Why Adjust an Expansion Valve?

Expansion valve adjustment is necessary when:

• The system shows poor cooling performance.
• The compressor is overheating due to low superheat.
• You notice frost forming on the evaporator or suction line.
• The refrigerant flow is either too high or too restricted.

Tools Required

• Properly sized wrench and a backing wrench.
• Refrigeration wrench for the adjustment screw.
• Protective gloves and safety glasses.

Step-by-Step: How to Manually Adjust an Expansion Valve

1. Locate the Valve

Find the expansion valve, usually located near the evaporator inlet.

2. Remove the Hex Cap

CAREFULLY remove the hex cap from the base of the valve using the correct wrench. Always use a backing wrench to avoid damaging the valve body.

3. Turn the Adjustment Screw

• Turn clockwise (1/2 turn at a time) to increase superheat.
• Turn counter-clockwise (1/2 turn at a time) to decrease superheat.

⚠️ Important: Make small adjustments and allow the system to stabilize before making further changes.

4. Monitor System Performance

Check superheat levels and cooling performance after each adjustment. The goal is stable operation with no frost buildup and efficient cooling.

Common Mistakes to Avoid

• Over-adjusting – turning too far at once can cause system imbalance.
• Ignoring leaks – always inspect for refrigerant leaks before adjustment.
• No gauges – always verify superheat with the proper gauges, not just by feel.

Professional Help vs DIY

While manual adjustment can be done with the right tools, many buyers and technicians prefer pre-calibrated control valves for reliability. At Qirun Auto Parts Co., Ltd., we manufacture precision automotive AC control valves that meet international standards, eliminating the need for frequent manual tuning.

Why Work With Qirun Auto Parts?

• 25+ years of experience in automotive AC components.
• Specialized in air conditioning control valves.
• Global supply chain – serving overseas customers with fast shipping.
• One-month product warranty for peace of mind.

Contact Us

If you are an international buyer or distributor looking for a reliable supplier of expansion valves and AC control valves, reach out to us today.

📍 Address: Foshan City, Nanhai District, Guicheng Street, Shanan 2, Shangyuan South Industrial Zone
📞 Phone: +86-13690143493
📧 Email: a13690143493@gmail.com

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Request a Quote

👉 Email us at a13690143493@gmail.com or call +86-13690143493 to request pricing and details. We are committed to supporting global buyers with professional AC control valve solutions.

Qirun Auto Parts Co., Ltd. – Precision AC control valve supplier since 2012, trusted worldwide.