How To Unbox and Assemble The Herman Miller Aeron Classic With Lumbar Support
You have just received your Herman Miller Aeron chair from OfficeLogixShop! This guide breaks the assembly down into simple, manageable steps to get you sitting comfortably as quickly as possible.
Step 1: Unboxing and Preparation
- Empty the box: Lay out all parts. You should have the seat assembly, the backrest, the star base, and a small box with the cylinder and casters.
- Keep the packaging: Do not throw away the box or wrap until your return window ends. Returns must be shipped back in the original packaging.
- Prep the backrest: Locate the four screws pre-installed on the backrest. Remove them and set them aside for the backrest installation.
Step 2: Base and Cylinder Assembly
- Install Casters: Flip the star base upside down. Push the casters firmly into the sockets until they click.
- Insert Cylinder: Flip the base back over and drop the gas cylinder into the center hole.
- Attach Seat: Flip the seat assembly over. Lower the seat onto the cylinder, pressing down firmly to secure the connection.
- Check Mechanism: If the mechanism cover has opened for any reason, simply click it back into place.
Step 3: The Backrest (The Diagonal Bolt Trick)
Proper alignment is vital for a smooth installation. Follow this specific order to make the process easy:
- Position: Place the backrest onto the chair frame so the holes align with the arm assembly.
- The First Bolt: Insert one bolt into a corner (for example, top left) and tighten it halfway.
- The Diagonal Move: Move to the opposite diagonal corner (for example, bottom right). Align the holes and insert the second bolt.
- Tighten to Align: As you tighten these two diagonal bolts, the metal yokes will pull closer together, making it much easier to insert the remaining two bolts.
- Finish: Install and tighten all four bolts completely to secure the backrest.
Step 4: Size Identification and Troubleshooting
If the backrest feels like it does not fit correctly, check these two items:
- Verify Size: Feel under the top upper lip of the backrest frame for Braille dots. One Dot is Size A (Small). Two Dots is Size B (Medium). Three Dots is Size C (Large).
- Fix the Yoke Gap: If there is a visible gap between the metal yoke and the plastic bushing, they need to be pushed together. Use your hands or a rubber mallet to gently tap them back into place.
Step 5: Cylinder Calibration (The Half-Turn Rule)
If your chair sinks or rises on its own, it likely needs a quick calibration:
- Open the Cover: Strike the bottom of the mechanism cover firmly to pop it open.
- Adjust the Pin: Use an Allen wrench on the internal set pin located inside the mechanism.
- The Rule: Only adjust in half-turn increments. Test the height function after every single half-turn to find the perfect balance for your weight.
Step 6: Lumbar Support Setup
- Installation: If not already installed, slide the lumbar pad onto the tracks on the back of the chair.
- Adjust Tension: You can slide the pad up or down for height, or remove and flip it over to change the thickness or tension against your back.
Frequently Asked Questions
Why is the backrest so hard to align?
This usually happens when the bolts are not installed diagonally. Using the Diagonal Bolt Trick pulls the frame into the correct position automatically.
Does a sinking chair mean the cylinder is broken?
Not necessarily. Most of the time, the internal pin just needs a half-turn adjustment with an Allen wrench to account for different user weights.
What tools do I need for assembly?
- Screwdriver: You only need a Phillips head screwdriver for the backrest bolts.
- Allen Wrench: This is needed if you require cylinder calibration.
- Rubber Mallet: This tool is optional but helpful for seating the bushings if you see a gap.