Office Chair Cannot Be Adjusted in Height

If your office chair cannot be adjusted in height, you can troubleshoot and repair it using the following steps:

Common Causes

1. Handle Displacement: The control handle has detached from the gas cylinder's pin, preventing the switch from being triggered.
2. Gas Cylinder Pressure Loss: Internal nitrogen leakage or aging of the seal ring results in insufficient support force. This is common in chairs with a long service life or poor quality, and may be accompanied by a hissing sound.
3. Mechanical Obstruction: Accumulation of grease, dust blockage, or rust on metal components in the base can obstruct the rebound of the pin.
4. Adjustment Mechanism Damage: Breakage of the handle or connecting components, or failure of the mechanical spring.
5. Improper Use: Someone sitting on the seat during lifting, or no load during lowering.
6. Other Mechanical Failures: Loose or broken connections in the five-star base or chassis, or hydraulic oil congealing due to low temperatures (common in low-priced products).

Troubleshooting Methods

1. Check Handle Connection: Invert the seat and confirm whether the end of the handle can touch the metal pin at the top of the gas cylinder. If misaligned, adjust the base fixing screws with a wrench.
2. Test Button Resistance: Press the handle repeatedly to feel for any stuttering or lack of resistance, indicating damage to the button mechanism.
3. Listen for Abnormal Sounds: Pay attention to any hissing sounds (indicating gas cylinder failure) or metal friction sounds (indicating mechanical failure) during adjustment.
4. Check Connection Stability: Shake the seat and observe for any looseness or abnormal sounds at the connection between the base and the seat cushion.
5. Temporary Recovery Attempts:
   • For heavier individuals, repeatedly press down and then quickly lift up to temporarily restore function.
   • Use a flat-head screwdriver to gently tap the air release valve (round metal ring) on the base; some older models can be restored by releasing air.
   • If delayed due to low temperatures, use a hairdryer to heat the metal parts of the base to above 20°C.

Repair Methods

1. Adjust Trigger Travel: If the handle cannot touch the pin, stick a coin or plastic piece above the pin to compensate for the gap.
2. Lubricate and Clean: Spray WD-40 or sewing machine oil into the gap around the pin and repeatedly press the handle until it rebounds smoothly.
3. Replace Gas Cylinder:
   • Disassembly: Invert the chair and gently tap the connection between the bottom of the gas cylinder and the chassis with a rubber mallet, then tap the top connection with the seat cushion.
   • Selection: Choose a universal model that complies with the national GB/T 2280 standard and has a 'Level 4 Certification', ensuring the load-bearing capacity matches.
   • Installation: Insert the new gas cylinder into the center hole of the base and press it vertically into the seat cushion until you hear a 'click'.

Precautions

• The design life of an adjustable chair is about 5 years. It must be scrapped if there is a hissing sound, automatic lowering, or cracks in the outer cylinder.
• Replacing the gas cylinder yourself poses safety risks; it is recommended to contact the manufacturer's after-sales service.