How do you adjust the spring tension on a roll up door?

A roll up door's springs sit inside the barrel, the steel pipe the curtain wraps around above the opening. Their tension is set at a tensioner on one end bracket, usually a ratchet wheel turned with a winding bar. The test is simple: if the door is easy to close but hard to open, it needs more tension. If it is hard to close but easy to open, it needs less. The adjustment itself is a job for a trained rolling door technician, because the springs hold enough force to cause a serious injury if a bar slips.

How the springs in a roll up door work

A sectional garage door has its torsion springs out in the open on a shaft above the door. A roll up door hides them. One or more coil springs run inside the barrel, fixed to the axle at one end and to the barrel at the other. As the curtain rolls down, it turns the barrel and winds the springs tighter. As it rolls up, the springs unwind and lift the weight of the slats.

That means a roll up door's springs are under the most tension when the door is closed, and the least when it is fully open. It is the reason technicians open the curtain before they work on the tensioner, and the reason a door that is stuck halfway is never a place to start loosening bolts.

Hot door or cold door: reading the balance

Rolling door makers use two plain words for a door out of balance. Janus International, a maker of storage and commercial roll up doors, explains both in its Model 650/750 tension adjustment sheet:

• A cold door has too little tension. It closes easily, feels heavy to lift and may slide back down when you let go partway up.
• A hot door has too much tension. It is hard to pull closed, wants to drift up, and can spring open when the latch is released.

To check yours, raise and lower the curtain a couple of times by hand and compare the effort each way. Janus also notes that springs relax over time, so it suggests checking tension at installation and again over the course of a year. A door that was balanced when it went in can turn cold after a few seasons of daily use.

The tensioner: ratchet, cam or tension wheel

Not every roll up door adjusts the same way. Most fall into one of three types:

• Ratchet tensioner. A toothed wheel on the end bracket with a pawl that drops into each tooth. A winding bar goes into the wheel, and each click locks the new setting. Janus's commercial Models 1000 and 1100 use a ratchet holding device, according to its guide to commercial spring tension.
• Cam action device. Found on many storage unit doors. The cam bites the axle to hold tension as the bar turns it.
• Set screws and a pipe wrench. Older and heavier rolling steel doors often hold tension with set screws on a tension wheel or collar. The screws are loosened, the axle is turned with a pipe wrench, and the screws are tightened again. Janus says that work is for qualified personnel only.

Look at the bracket on each side of the barrel. The side with the wheel, the cam or the collar is the tension side. If you cannot tell which type you have, do not guess, since a set screw loosened on the wrong bracket can let the axle spin.

How a technician adjusts the tension

The order matters more than the tool. For a cold door that needs tension added, Janus's sheet has the door raised until the bottom bar sits about ten inches below the header, then a winding bar inserted into the ratchet and turned slowly clockwise until the door starts to lift and the ratchet clicks into the next tooth. For a hot door that needs tension removed, the curtain goes fully open, the technician puts light pressure on the bar to lift the pawl, and lets the wheel turn back one groove under control.

A good technician makes one small change at a time and tests the door after each. The goal is a curtain that lifts with steady, even effort and stays where you leave it partway up. Before leaving, we also look at the guides, the bottom bar, the slats and the lock, since a door that drags in a bent guide can feel cold when the springs are fine.

Why we tell business owners and tenants not to do it themselves

The spring force is stored in the barrel whether you can see it or not. A winding bar that slips out of a ratchet, a screwdriver used in place of a bar, or a set screw loosened under load can spin the wheel faster than a hand can let go. Janus requires its doors to be installed by trained rolling door technicians and maintained by qualified people for that reason.

If you rent a storage unit, tell the facility office: the door belongs to the facility, and the manager can have it fixed. If you own the building, keep the door closed and locked and call a commercial door technician. Our page on storage unit doors that are hard to open covers what you can safely check first.

When adjusting the tension is not the fix

• A broken spring. A loud bang from the barrel, followed by a door that suddenly feels far heavier, usually means a spring broke. More tension will not help. The spring needs replacing, and on a busy door a high cycle spring may be worth it.
• A spring that keeps going cold. If the door needs tension added every few months, the spring is near the end of its life.
• A dragging curtain. Bent guides, dented slats or worn windlocks make a door hard to move in both directions. That is a guide or curtain repair, not a tension problem.
• A door that will not move at all. If you need to get the door open now, see how to open a roll up door manually, then have it looked at before it runs again.

Common questions

Is a roll up door spring under tension when the door is up or down?

Down. The springs wind tighter as the curtain rolls down and relax as it rolls up, so they hold the most force with the door closed.

Can you put a stronger spring on a roll up door?

Not as a fix for a cold door. Springs are sized to the weight of the curtain. A spring that is too strong makes a hot door that is hard to close and hard on the lock. The right answer is a spring matched to the curtain, or new springs when the old ones have worn out.

How often should a roll up door's tension be checked?

At installation and then periodically through the year, as Janus suggests. Busy docks and storage facilities fit it into a planned maintenance visit.

How G Brothers helps

G Brothers repairs roll up and rolling steel doors for warehouses, shops, storefronts and storage facilities across Denver, Lakewood and the west metro, and we work on self-storage roll up doors regularly. Our technicians carry parts on the truck for most repairs, and we can send a certificate of insurance, usually within 24 hours, when your property manager asks for one. See roll up and rolling steel door repair, commercial spring repair and storage unit door repair, or call us to have the tension set right.

Sources

• Janus International, Model 650/750 Tension Adjustment
• Janus International, Commercial Spring Tension