DASMA TDS 165 - Manual Operation of an Automatic Garage Door

During a power outage, most homeowners reach for the red cord hanging from the garage door operator. DASMA TDS 165 explains what that cord actually does and how to use it safely without leaving your door disconnected from the opener for days afterward.

What this data sheet says

The red cord is the emergency release, a mechanism that disconnects the door carriage from the operator trolley so the door can be moved manually. TDS 165 covers both the disengagement and re-engagement procedures:

"Pulling the emergency release cord while the door is in motion can cause the door to drop unexpectedly. Always stop the door before using the cord."

Key points from TDS 165:

• Disengage from the closed position. Pull the red cord only when the door is fully closed, not mid-travel. Disengaging while the door is moving mid-travel can cause an uncontrolled drop.
• Check spring balance before moving manually. A properly balanced door should lift smoothly with one hand and stay at mid-travel without support. If it drops or flies up when you let go, the springs are out of adjustment and it is not safe to operate manually.
• Lifting a heavy door manually. Even a balanced door may weigh 100 to 200 lbs. Grip the lift handle or a panel brace, not the bottom edge. Lift with your legs.
• Re-engaging the trolley. After power returns, pull the release cord toward the door (not down) to re-connect the carriage to the trolley, then run the operator once to let the automatic mechanism seat itself. Some operators require you to pull a second cord (or the same one in a different direction) to re-engage.
• Security risk. A door left in manual-release mode cannot be locked by the operator. From outside, a thief with a wire hook through the top weather seal can sometimes trip the release cord. TDS 165 recommends re-engaging the operator as soon as power is restored.

When it applies

Power outages affect everyone in the Denver area, including during winter storms when the garage may be the only way in or out. TDS 165 is also relevant when:

• An operator motor fails and the door needs to be moved for vehicle access
• The operator is being serviced or replaced and the door must be run manually
• A technician needs to test spring balance with the operator disconnected

For example: if a December blizzard knocks out power and you need to get your car out for an emergency, pulling the red cord and lifting manually is the correct procedure. But TDS 165 warns that if you do this, lock the door with a slide bolt or padlock before leaving the house, because the operator can no longer secure it.

What this means for you

Practice the release before you need it. Most homeowners discover the emergency cord for the first time in the dark during a power outage, under stress. Open the garage door (with power), then pull the cord from the floor level to see how much force is needed and where the carriage disconnects. Then run the door with the opener to re-engage it.

Know how your specific operator re-engages. Some models re-engage automatically when you run the motor; others require manually sliding the carriage back along the trolley rail first. Check your operator's manual for the exact procedure, or ask your installer.

After any manual operation, verify the door reverses properly on the first motorized cycle. Occasionally a door that was manually slammed shut can bind the carriage and cause the opener to skip the reverse.

If you are unsure whether your springs are properly balanced, G Brothers can test balance and adjust springs before an outage season leaves you guessing.

Full text and source

Download DASMA TDS 165 from the official TDS index at https://www.dasma.com/technical-data-sheets/.

This entry covers residential sectional garage doors with standard overhead trolley-type operators. Jackshaft operators (side-mounted) use a different release mechanism described in the operator manual.