A door closer that slams, drags, or fails to latch is one of the most common maintenance complaints in commercial buildings. The good news is that in most cases, adjustment is straightforward — no replacement required.
Step-by-step adjustment:
Step 1 — Identify the valves
Most closers have the adjustment screws on the end cap of the closer body, though some models place them on the underside. Consult the manufacturer's datasheet if you're unsure. Common layouts:
- **dormakaba TS closers:** adjustment valves on the narrow end of the body, labelled or marked with arrows
- **GEZE TS closers:** similar end-cap arrangement
- **Briton closers:** often two screws on the end, sometimes one on the underside for backcheck
Never remove a screw fully — these are valves, not fixings. Removing them releases hydraulic fluid.
Step 2 — Test the current behaviour
Open the door fully and let it close. Observe:
- Does it close all the way and latch?
- Does it slam or bang?
- Does it slow down at the end but fail to engage the latch?
- Does it move violently when opened wide?
This tells you which valve to focus on.
Step 3 — Adjust closing speed
Using the appropriate key, turn the closing speed valve:
- **Clockwise** = slower (more restriction)
- **Anti-clockwise** = faster (less restriction)
Make small adjustments — a quarter turn at a time — and test between each. Hydraulic closers respond gradually; there's no need for large adjustments.
Step 4 — Adjust latch speed
Once the main closing speed is correct, adjust the latch speed separately. The door should maintain enough momentum to click the latch into the keep cleanly, without banging.
Again: quarter turns, test after each adjustment.
Step 5 — Adjust backcheck (if needed)
If the door swings open too easily and risks hitting the wall, tighten the backcheck valve (clockwise). If the door feels like it hits an invisible wall at around 70°, the backcheck is too tight — loosen it slightly.
Step 6 — Check spring power
If the door consistently fails to close against a draught, or requires significant force to open, the spring power may need adjustment. On most closers this is done via a separate power adjustment — often a hex socket on the main body or an adjustable arm.
Increasing spring power will make the door harder to open but more reliably self-closing. This is particularly important on fire doors, which must close from any position under BS EN 1154.
Need a replacement closer?
We stock a full range of overhead door closers from dormakaba, GEZE, Briton, and more — with same-day despatch on orders placed before 2pm. If you're not sure which model you need, our team can help identify the correct replacement from a photo or part number.
Browse door closers → https://www.doorspares.com
