About Door Closer and an Adjustment Guide
About Door Closers and an Adjustment Guide
1. Rack & Pinion (Standard/Regular Arm)
This is the most common commercial closer. It uses a gear and toothed bar mechanism.| Function | Typical Label | Action | Adjustment Effect |
| Closing Speed | S (Sweep) | Clockwise | Slows the door from $90^\circ$ down to about 15deg. |
| Latching Speed | L (Latch) | Clockwise | Slows the final 15deg to prevent slamming. |
| Backcheck | BC | Clockwise | Increases resistance during the opening cycle (prevents wind from whipping the door open). |
| Spring Tension | Power | Clockwise | Increases the overall physical force needed to open and close the door (usually an end-nut). |
Pro-Tip: If the door is an external door in a windy area like Canberra, you’ll want a higher Backcheck setting to protect the hinges.
2. Cam Action (Slide Rail / Track)
Cam action closers use a heart-shaped cam instead of gears. They are much easier to open (low opening force) but require precise adjustment because they have more "snap" at the end.
Latching Speed: Unlike rack and pinion, cam closers often have a "Latching Action" that actually increases force in the last few degrees to overcome door seals.
Closing Speed: Regulated similarly to rack and pinion via the "S" valve.
Spring Tension: Often found at the end of the closer body. Adjust this if the door isn't overcoming the air pressure (stack effect) of the building.
3. Slide Rail (Normal / Low Profile)
Often used for aesthetics, these closers use a single arm that slides within a metal track.
Closing/Latching: These are usually found on the side of the body. Because slide rails have less leverage than a "scissor" arm, you may need to set the Latching Speed slightly faster (counter-clockwise) than you would on a standard arm to ensure it clicks shut.
Backcheck: Crucial for slide rails. Without a scissor arm to provide mechanical resistance, the hydraulic backcheck is the only thing stopping the door from hitting the wall.
Properly adjusting your door closer ensures safety and longevity of the hardware. Follow these steps for Rack & Pinion, Cam Action, and Slide Rail closers.
| Valve Label | Function | Clockwise (CW) | Counter-Clockwise (CCW) |
|---|---|---|---|
| S (Sweep) | Closing Speed (90° to 15°) | Slower | Faster |
| L (Latch) | Latching Speed (15° to 0°) | Slower | Faster |
| BC | Backcheck (Opening Resistance) | Increases Resistance | Decreases Resistance |
Adjustment Sequence
- Spring Tension First: If the door is too heavy to push, or won't close against the latch, adjust the spring power nut on the end of the body.
- Backcheck Second: Open the door firmly. It should start to meet resistance at about 70deg. Adjust the BC valve until the door "cushions" before it hits the wall.
- Closing Speed (Sweep): Open the door to 90deg and let go. It should take approximately 5 to 7 seconds to reach the 15deg mark.
- Latching Speed: This is the "final snap." Adjust the L valve so the door closes firmly enough to latch, but quietly enough not to disturb the household.
Warning: Do not back valves out more than 2 full turns to avoid hydraulic fluid leakage.