The door rises six or eight inches, shudders, and reverses — or just sits there humming. Nine times out of ten the opener isn’t the problem. The door has gotten too heavy for the motor to lift, and the force limit trips. That weight usually means a broken torsion spring.
What the symptom actually tells you
A residential opener is rated to pull a certain amount of force — typically ½ or ¾ horsepower. When the counterbalance system works, a 16×7 door feels like 10 or 15 pounds to the motor. Snap one spring on a two-spring system and the door weighs 150-plus pounds. The opener hits its programmed force ceiling inside the first foot of travel and kills power to protect the gears.
You’ll hear the motor run for a second or two, then click off. The lights on the powerhead usually flash a code: five blinks on most LiftMaster and Chamberlain units means “excessive force detected.” Genie and Craftsman flash differently — check the sticker on the motor cover — but the meaning is the same.
Confirm it’s the spring before you touch anything
Stand inside the garage with the door closed. Look at the torsion shaft above the door. You should see one or two springs mounted on a stationary cone at the center bracket. A healthy spring is a tight coil with a paint stripe running straight down its length. A broken spring shows a clean gap — usually two to three inches wide — where the coil snapped and unwound. The paint stripe spirals like a corkscrew.
If you have a single spring, the door is now dead weight. If you have two and only one broke, the door will still try to move but it will crook sideways because the cable drum on the broken side goes slack. That sideways bind adds friction and makes the opener quit even faster.
Do not pull the emergency release and try to lift the door by hand unless you know what 150 pounds feels like and you have a solid grip on the bottom rail. The door can crash down the moment it clears the horizontal tracks.
Other causes that mimic a broken spring
Photo-eyes misaligned or blocked. The door will start down, not up. But if the eyes are wired backwards or the logic board is glitchy, you can get an immediate reverse on the up cycle. Wipe the lenses. Make sure both LEDs are solid, not blinking.
Broken cable or cable off the drum. The door jams crooked in the tracks after a few inches. You’ll see slack cable at the bottom bracket or a drum that’s spun loose. This often happens because a spring broke and the sudden slack threw the cable.
Stripped opener drive gear. Common on older chain-drive LiftMaster units with the nylon gear. The motor whines but the chain doesn’t move — or moves in jerks. Pull the release. If the door moves freely by hand, the gear is gone.
Bent track or frozen roller. The door binds at the same spot every time. Spray the rollers with silicone. If one roller doesn’t spin, the opener sees the drag as force overload.
What a spring replacement involves
We carry standard residential torsion springs on the truck — 1¾-inch and 2-inch inside diameter, wire sizes from .207 to .262, lengths cut to the door weight. The job takes about an hour: secure the door, unwind the remaining spring, swap both springs so they age together, wind to the correct turn count, and reset the opener force limits.
Two springs on a standard double door cost the same labour as one. Replacing only the broken side saves nothing and guarantees a second service call inside of two years.
Extension-spring doors (the kind with springs stretching along the horizontal tracks) are less common in Metro Vancouver but we stock those too. The safety cables have to be intact. If they’re missing we install them — required by code and common sense.
When to call versus when to troubleshoot
Check the photo-eyes. Check for a visibly snapped spring. Check that the trolley didn’t disconnect itself — the red rope hangs straight down when engaged. Beyond that, stop.
Torsion springs store enough energy to shatter a winding bar or take fingers off. The winding cones are hardened steel; a slipping bar at 30 foot-pounds of torque doesn’t forgive. We’ve seen DIY attempts that bent the shaft, cracked the center bracket, and still left the door unusable.
Flat-rate quote, two-year workmanship warranty, same-day service in Richmond, Surrey, Delta, Burnaby, Vancouver, and the North Shore. Trucks carry LiftMaster, Chamberlain, Genie, and Clopay parts. Call 778-873-7282 or email info@upanddowngaragedoors.ca.