Door Closer Maintenance, Repair and Adjustment Info

EXCERPT: For adjustment and repair of Door Closers, often used in offices and commercial buildings.  Also known as: Mechanical door closer, office door closer, automatic door closer.

For information on pneumatic storm door closers, see this article: Storm Door Closer Maintenance, Repair and Adjustment

Disclaimer: This information may be inaccurate, incomplete, or dangerous.  You are responsible for your actions.  I caution you to NOT disassemble the main cylinder, your closer may have a strong spring inside that can cause serious injury if an end cap is removed.

This article is an updated version of the original page.

Basic Operation

  • Hydraulic Door Closers close a door automatically at an adjustable speed.
  • A Door Closer is usually mounted at the top of a door or above it on the jamb.  There are also internal models that are installed hidden inside the door frame for a cleaner look.
  • An internal Spring applies force to the Arm to close the door.  Hydraulic fluid (oil) flows through pathways inside the closer.  The resistance/restriction to fluid flow determines the door closing speed.
  • Spring strength and adjustment (if any) varies by model.  Heavier doors require stronger door closers.
  • Door closers are matched to their application, based on door size and weight, and the corresponding strength needed to close them properly.
  • Adjustable Spring tension allows models so equipped to work well for doors of sizes within their range of adjustment.

The operation of a door is controlled by the Door Closer in 3 basic zones:

Adjustment

Instructions here are for a properly functioning door closer.  If your door closer is not functioning properly, see Troubleshooting section before adjusting.

  • Adjustment screws usually require a hex wrench.
  • Your closer may have a cover that must be removed before you can access the adjustment screws.
  • Do not unscrew the adjustment screws, they will fall out, and oil will spill!
  • Generally, turning a screw Clockwise will increase resistance or slow the door, Counter-Clockwise will do the opposite.
  • Adjustments can be sensitive, start with a 1/4 turn

Adjustment: Things to consider

  • I prefer a slow-moderate sweep and a slow, quiet latch.  Sometimes environmental factors do not allow an ideal adjustment.
  • If your door won’t latch when adjusted to a slow latch speed, perhaps your latch bolt is not functioning smoothly or installed correctly.
  • Perhaps your door requires a higher closing force, adjust your PA (power assist) or Spring Tension if available
  • Variables to take into account:
  • Weather conditions: Wind, Snow, Ice, etc.  You may need to adjust your door to close properly across ALL conditions
  • HVAC: Positive or Negative pressure in your building.  Some ventilation systems will cause the door to blow open or pull shut, you may need to adjust your latch speed to a little faster to overcome a positive pressure, or slower to handle a negative pressure.
  • Your latch zone may be lengthened or shortened by adjusting your arm length.
  • Adjusting your arm length may also cause your max open angle, or backcheck zone to engage earlier

Typical door closer

e.g. LCN, Norton/Sargent/Arrow may have the following adjustments:

Adjustments (typical)
S Sweep Rate adjustment for long closing swing of door
L Latch Rate adjustment for short latch swing of door
BC Backcheck Adjustment to slow/limit the door’s max open angle
PA Power Adjust Adjustment for spring tension (less common)

To adjust a typical closer:  Adjust a little at a time – try a 1/4 turn to start, open the door between adjustments to check the difference.

Adjust in this order:

  1. Sweep speed (and Power Adjust if necessary/applicable)
  2. Latch speed
  3. Backcheck
Norton Adjustment Screws

Picture of Norton Adjustment Screws

Kawneer door closer

For Kawneer models with a single combination adjustment for Sweep and Latch. One screw adjusts both settings:

Kawneer Adjustments
Screw type/loc. The Sweep and Latch are both adjusted with a single screw
Beveled Edge (see chart below) Sweep Sweep is adjusted by turning screw CW to increase resistance/slow closing speed
Latch Latch is adjusted  from least to max within 1 revolution
Opposite side Backcheck Adjustment to slow/limit the door’s max open angle

To adjust Kawneer closers:  Set your Sweep speed first, then turn adjustment screw +/- one half turn in either direction to attain proper Latch speed.

Graph of Kawneer adjustment screw function

Picture of Kawneer Adjustment Screws

Troubleshooting

Most problems are caused by low oil.

Low oil level can look like:

  • Door swings too fast to a point mid-swing, at which it closes at a normal slow pace
  • Door swings closed without any resistance, slamming against door jamb/frame
  • Changing adjustment screws is of no effect
  • Oil puddle underneath door closer unit
  • Oil drops on bottom of arm

Oil loss is usually due to:

  • An adjustment screw being removed
  • Leaking adjustment screw seals (o-rings)
  • Leaking arm shaft seals (o-rings)
Picture of Kawneer Adjustment Screw with new O-Ring seal installed

Kawneer adjustment screw with o-ring replacement

Repair

Smaller Door Closers are relatively inexpensive, figure in your time, and consider replacing them.

Heavy Duty Door Closers can be expensive and hard to find replacements for

Check to see that your door closer is not under warranty.  The following instructions may void any warranty you have.

Repair seals / Refill Oil:

Consider Hydraulic Jack Oil in the automotive section of a major store.  I have also successfully refilled door closers using 3-in-1 household oil

  1. Wear Safety Glasses
  2. Note the leaks, and their apparent origin
  3. Remove the door closer unit from the door or top jamb
  4. Move unit to a suitable workspace (oil will drain, and sometimes squirt from unit during refill process)
  5. Remove adjustment screws or other hardware to gain access to seals
  6. Remove seals, or take the screw/shaft with the o-ring on it to the hardware store
    • Match the o-ring with a new one at the hardware store
    • optionally, buy an assortment of o-rings from Harbor Freight
  7. Typical: re-insert BC adjustment screw, tilt and hold closer so that it’s on it’s end, with the S and L adjustment screw ports facing upward
  8. Fill port(s) with oil, slowly moving the closer Arm to distribute oil internally.  If you move too fast oil may squirt out!
  9. Fill to top and re-insert adjustment screws with fresh seals

Tip: If you want to save yourself some time adjusting, count the number of turns while you remove the adjustment screws.  When you reassemble you can turn them in the same number of times to get close to your original settings.

Arm Shaft Seals:  If you’re changing the Arm shaft seals, here’s a few tips.  Be careful if removing the internal Spring.  The Arm shaft seals on your closer might be accessible after removing the retaining ring on the pinion shaft (where the arm is attached to the closer) note the position of the arm on the pinion shaft, you will need to correctly align the arm and pinion shaft when you reassemble.  Replace the o-rings on both sides of the pinion shaft

Pinion Shaft Illustration

Pinion Shaft Illustration

51 thoughts on “Door Closer Maintenance, Repair and Adjustment Info

  1. Can a door closer, more specifically a floor door closer, ever build up pressure on the inside, especially if it is not in use, even if it has lost some oil? If they are not adjusted right where someone tries to force the door close, that would be the only situation where pressure would build up until the door is released. Love your feedback on this.

    PS: I have been learning how to install various brands of door closers on my demo doors and use the upmost care when I adjust them so everything works properly. I’ve paid for everyone of them and that is why I read the instructions very carefully before I did anything. I’m not lucky enough to have everything given to me.

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