Garage Door Opener Basics Q & A by Bob Fleming from Handymanusa.com

Questions organized and answered by Bob Fleming - www.handymanusa.com

Garage Door Opener Basics 
Garage Door Opener = GDO

What is an automatic garage door opener?
What to specify if you have a problem
Instructional Manual

It is an electrical device that will open a garage door for you with a hand-held remote transmitter (clicker) or a wall-mounted push button or a numeric keyless pad controller (keypad). Neat idea when the weather is bad and you don't want to get out of your car. The door must be a sectional roll-up type or a one piece (slab) door that pivots on 'Side hardware or a side track. The door can be either wood or metal. The door can be a single width size (nominally 8' wide by 7' high), or a double width size (nominally 16' wide by 7' high). The door must work easily and safely by hand before you connect the garage door opener. See the garage door safety section for safety tips, adjustments, etc. 

There is at least one manufacturer now that offers a computer-controlled drive mechanism that uses no chain or screw. The body of the unit sits directly above the door, rather than in the middle of the ceiling. This is particularly helpful in garages that have limited headroom, and it leaves more garage ceiling space open for storage.

What to specify if you have a problem:

Is the garage door opener a chain drive, screw drive, belt drive, or trac drive opener? Is the door a one piece (slab) type or sectional (roll-up) door? Does the problem occur with both the remote transmitter and wall push button?

Instruction manual:

If you move into a home with a garage door opener and there is no manual, it really helps to get one, and get it before you need it. Ask local garage door stores if they have an extra copy for that specific brand/model, or you might be able to get help from the manufacturer's websites.

Buying New Openers

What type of Garage Door Opener is considered best? How much power do I need?
Are Garage Door Openers actually safe?
Can I add these safety features to the older Garage Door Openers?
What is the lifespan of a Garage Door Opener?
Are Garage Door Openers reliable?
Are Garage Door Openers secure?
Can I install a Garage Door Opener myself?
What brands do you recommend?
My garage door is very heavy; will a Garage Door Opener operate it?
My garage floor is uneven; will a Garage Door Opener work for me?
I have a separate garage and no door or windows to enter the garage. How do I get inside if the power goes out?

What type Garage Door Opener is considered the best? How much power do I need?

There are three types of garage door openers available: screw drive, chain drive (in some cases, chain/cable), and friction (trac or belt) drive. The most reliable long-term is the screw drive, while the chain drive may work fine for you. Both will move a double garage door with 1/2 hp, and this is the most commonly size sold. 1/3 hp will handle a single door ok. With a screw drive operator, the setting of the up/down position is reliable and action is solid. With a chain drive operator, the up/down setting is sometimes difficult, and the chain will stretch in time making it necessary to reset the up/down positions. Also, chains do occasionally break and the gears are more fragile. Friction drive is very problematic and parts are becoming rare, but they may work on a single door; they are wonderfully quiet (especially when you have a room above the garage), when they work right.

There is one brand GDO, Marantec, that currently has motor units with swappable tracks/rails. Bought a Q-Line Marantec chain drive opener and added a room above the garage and now you want to switch to a quieter belt drive opener? Just purchase a Marantec belt drive track and swap out the chain drive track. Another plus about Marantec's Q-Line GDOs is their LIFETIME WARRANTY on parts, not accessories. For more on Marantec GDOs; visit the manufacturer website at www.marantecamerica.com.

Newer premium units use a rolling code systems that change the code every time you use the transmitter or keypad. They are worth the extra money for the added security, and many times are the only type available.

Are GDOs actually safe?

They are probably a lot safer than your car! GDOs now come with two safety features, but these were not available on older GDOs. First, the down force can be adjusted so that if the door hits something in the way, it will reverse and open all the way. This is particularly true of the screw drive models, but this adjustment can be difficult if not impossible on older chain drive models, The other safety feature now required since 1997 is a light beam sensor across the bottom of the door opening. If anything stops the light beam, the door will start down, reverse and go back up. These light beam sensors are reliable and easy to set up.

No. The down force adjustment is inherent in the mechanical design and currently there is no add-on light beam sensor kit for garage door openers. In order for your opener to apply safety beam sensors, they would have had to come with them or the printed circuit board would have to have an option to add them.

A screw drive GDO should last 8-12 years (much longer if well taken care of) if lubricated twice a year, more often in colder temperatures. A chain drive GDO will eventually experience chain stretch and will have to be adjusted; the gears inside also take a beating. Friction type openers (trac or belt) last just as long with the exception of the belt or trac and trac sprocket. These parts commonly where out. Parts are still available but are becoming harder to find.

Are GDOs reliable?

Yes, but they do need some maintenance, mainly lubrication of the screw or chain as well as the door and all other moving parts. Use a good quality lubricant - it doesn't need to be expensive.  Buy LOW TEMPERATURE lubricant if you live in cooler climates. Check our accessories section for LOW TEMP lubricants. Do not use WD-40 except to wash off old lube, since you need a lubricant that has some body; the operating parts of a door or GDO are under great pressure, so you need a high-pressure or gear lubricant. Many of the problems encountered with GDOs when the weather gets cold comes from the lack of lubrication.

And sooner or later, the battery in the transmitter will need to be replaced.

Are GDOs secure?

Older types of openers used an analog transmitter/receiver. These are the models you used to hear about opening and shutting garage doors when airplanes flew overhead. If you move into a home that has one of these, replace it as soon as you can! Not only are they not secure, but they do not have up-to-date safety features.  

The newer model openers use digital transmitters and receivers. With these, you can set the digital code to something unique so your transmitter will not accidentally operate your neighbor's door, and they are not operated by overlying aircraft. However, sophisticated burglars developed scanners that can find your code and get in. Most recently, digital GDOs use a rolling code technique (For Genie it is called "Intellicode", Lift-Master = "Security+", Linear/Moore-o-Matic = "MegaCode", Stanley = "Securecode", etc..) that cannot be easily scanned. They are about as secure as you can get.

It is not difficult to add the rolling code feature to an older GDO.  Many manufacturers make universal converion kits that will install on any machine, such as the Genie GIRU-1T and Lift-Master 635LM-1T universal converion kits.

For added security, install a GAPLOCK automatic garage door locking system and install it on your garage door and wire it to the GDO to protect the largest door in your home.  Buy garage doors without windows. That's how burglars are able to see the manual release lock (red pull cord) and use a coat hanger or metal wire to pull and release it and open the door manual.  Gaplock will prevent this from happening.

Can I install a GDO myself?

Yes, if you are reasonably handy. It takes 2-3 hours for an experienced person to complete the installation; about 5 hours if you have never done one before. You will need a 6' stepladder and an assortment of tools; a cordless drill screw driver will be very handy. It is not necessarily a fun task, but you will save some money since garage door opener installers charge $75-125 for installation. When you attach the GDO to a metal sectional door, it is recommended that you install a 2x2" perforated metal angle vertically from the top to the bottom of the top panel, and attach the GDO to that. While metal sectional doors are very durable, they need that bracing for the force of the GDO.

What brands do you recommend?

The only thing that can be said here without offending someone is that most of the GDO problems reported on AAARemotes daily free technical calls are with Stanley units (which may be why they are out of business). Genie makes a great screw drive unit, while Chamerlain makes top of the line chain drive units. Chamberlain makes many of the Sears models. LiftMaster is also made by Chamberlain. Be cautious about any other brands, particularly store brands; you may not be able to get parts and service later if you need it.

If the door is balanced correctly, the GDO will lift it with no problems. Sometimes a heavy wood door becomes a problem when it gets wet. In that case, call in a professional garage door installer and ask about heavier springs. Do not try to install springs yourself, it could be dangerous, even fatal.

My garage floor is uneven; will a GDO work?

If you can open the door manually without a struggle, a GDO will work.

This is a very serious concern, and there is a solution for it. It comes in the form of a key-operated switch or "rip cord" on the face of the door. You use a special key to pull the lock cylinder out, then pull out the cord, it is attached to the GDO release cord inside. Once you release the connection of the garage door to the GDO carriage assembly, you can open the door manually.

You have a separate garage and no key-operated switch and have locked yourself out? Our only recommendation is to call AAA and have them tear down the door.  You see where a simple $8 dollar part turns into a $600+ garage door and GDO replacement project.

Fitting a GDO in a tight space

I have a one piece "slab" door but there is a big beam running parallel to the door just a couple feet behind it. Can I fit a GFO in this space?
I have a sectional door but there is a big beam running parallel to it just a couple inches behind it, Can I fit a GDO in this space?
Same deal, except the ceiling is drywalled and I can't tell what is up there.
I have a sectional door but I can't mount a GDO in the center of the garage. Can I put it off to one side?
I have a one piece slab door but cannot mount a GDO in the center. Can I mount it to one side?

I have a one piece "slab" door but there is a big beam running parallel to the door just a couple feet behind it. Can I fit a GDO in this space?

There is at least one manufacturer now that offers a computer-controlled drive mechanism that uses no chain or screw. The body of the unit sits directly above the door, rather than in the middle of the ceiling. This is particularly helpful in garages that have limited headroom, and it leaves more garage ceiling space open for storage.

Same deal, except the ceiling is drywalled and I can't tell what is up there.

It is unlikely there is some major duct work in that space, but cut a peek hole and check to be sure there is no plumbing in the way. If there is something in the way, try again in the next joist space to see if you can find one that is clear, then proceed. If it looks like it will work, cut away the drywall between the two joists. Before you actually mount the GDO there, line the space between the two joists with 5/8" firecode drywall; use corner bead, tape and fill for a thorough job. In this way you will keep the firewall rating intact between the garage and the house above. Then install the GDO.

There is at least one manufacturer now that offers a computer-controlled drive mechanism that uses no chain or screw. The body of the unit sits directly above the door, rather than in the middle of the ceiling. This is particularly helpful in garages that have limited headroom, and it leaves more garage ceiling space open for storage.

I have a sectional door but I can't mount a GDO in the center of the garage. Can I put it off to one side?

Yes, the two sides of a sectional door are kept in line by the pulley shaft running across the top of the door. So you can attach the GDO to the door anywhere in its width; it is better to have the GDO attached as near the center as practical.

Newer openers have been developed which mount on the side of the garage door as well as directly above of the garage door to free up space from the center of the ceiling of the garage. There is at least one manufacturer now that offers a computer-controlled drive mechanism that uses no chain or screw. The body of the unit sits directly above the door, rather than in the middle of the ceiling. This is particularly helpful in garages that have limited headroom, and it leaves more garage ceiling space open for storage.

I have a one piece slab door but cannot mount a GDO in the center. Can I mount it to one side?

No; forget it. Consider replacing the door with a sectional door, but remember that a sectional door moves farther into the garage.

The trolley on my screw drive opener is broken. Is it difficult to install a new one?
The chain on my opener came off the gear. Can I put it back on?
The GDO went out in a thunderstorm. What do we do?
The door remote is lost. How do I buy the right one?
How do I set the code on an external keypad?
How do I get a rolling code type GDO set up?
The GDO track is torn loose from the door header. How do I repair that?

The trolley on my screw drive opener is broken. Is it difficult to install a new one?

Depends. If the motor box is mounted on straps or can be shifted around some, you can unfasten the door end of the track from the header and drop it down or to the side to slip out the old trolley and put in a new one. Disconnect the trolley from the door and the screw first, of course, and loosen any wires that go from the track to the door header. Have the new trolley at hand when you take the track loose from the header.

If you can see that it is not possible to twist the motor box around, you will have to take the whole assembly down, or at least loosen it and hang it from something, Nuisance job, but not really difficult. It would be nice to have a helper.

Some tracks are assembled in three sections, but trying to undo one of those joints with the unit in place is difficult at best; not recommended.

The chain on my opener came off the gear. Can I put it back on?

Yes. Get on a stepladder and watch as the motor operates to see if the drive gear turns. If not, you have a serious internal problem and may be best off to replace the unit. If the gear turns ok, then find the adjustment screw near the gear to adjust the chain tension. Unplug the unit and back off the adjustment so you can fit the chain back on the gear. The chain will be greasy so using disposable plastic gloves is a good idea. Then adjust the tension so the chain sags just so it doesn't drag on the track.

If there is no tension adjustment on your GDO motor box, you will have to adjust the chain with the turnbuckle device that ties the two ends of the chain together. This is a bit more tedious than the other method, but it works.

The GDO went out in a thunderstorm. What do we do?

Call a local rep or store selling that brand and ask them if the unit is repairable and how much. It will probably require a new circuit board inside the motor box. If it is going to cost more than a new unit, get a new unit. Check your homeowners insurance first to see if repair and/or replacement is covered. And with 20-20 hindsight, plug it into a surge suppressor. A surge suppressor may or may not protect the new one from nearby lightning strikes, but it is a worth a try. In buying a surge suppressor, check the ratings carefully; cheapest is generally not best, but it need not be expensive either. After you read a couple boxes for specifications, you should be able to tell what you need.

Replacing the circuit board is not difficult if you are handy. Unplug the unit, open the motor box and see how they fastened the circuit board in place. Unplug it and replace it. Remember that you are dealing with sensitive electronics when you handle a circuit board and don't touch the components or circuit traces; handle it by the edges.

For Liftmaster/Chamberlain/Wayne-Dalton/True Guard/True Value/Master Mechanic/Garage Master/Access Master/Raynor/Sears/Craftsman:
Use LIGHTNING SUPPRESSOR KITS which implement MOV - Metal Oxide Varistor to help decrease the chances of the circuit board (and safety beam sensors) from getting fried.  Lightning Suppressor kits vary depending on the model of your machine.

The door remote is lost. How do I buy the right one?

Look at the motor box carefully and see if it has any code-setting switches; they are very small and they may be inside the plastic light cover or on back. The label on the box may give you some clue. If there are no code switches and there is no label mentioning digital codes, you probably have an old analog type GDO. Best bet is to replace it with a new one. All the new ones are digital coded. We also need to know the frequency of the opener or transmitters in order to find the most compatible replacement.

If you find code setting switches, count the number of switches; there should be 8, 9, 10 or maybe 12, all on one little block. They call these Dip Switches because they look like a Dual Inline Plastic integrated circuit. With that information and the brand name, you should be able to find a workable remote at a on our site. If the new remote has more switches than the GDO, just ignore the extra ones. Some of the new remotes are remarkably small, even key-chain size. Do not get an "Intellicode" or rolling code remote unless the GDO is labeled such.

If you find a "learn", "smart" or "remote" programming button, then we'll just need to know the brand and frequency to find the exact match. Learning remotes are typically code rolling but the frequency always remains the same, only the access code changes.

Most of these remotes come with setup instructions. When you set it up, you generally match the switch settings on the remote to those on the GDO. If the GDO is a rolling code type, get that type of remote and follow the directions that come with it.

How do I set the code on an external keypad?

There are two types of keypads, wired and wireless. The wireless type are programmed about the same as a remote, but where you would program dip switch settings you would type them into the code keypad. The wired type should have code setting switches on the motor box or they may also require manually inputting them through the code keypad. You might be able to find a website for the manufacturer and get more help or programming instructions online.  

How do I get a rolling code type GDO set up?

There is usually a 'learn" sequence that you activate on the motor box. Look for such a button to see if you can figure it out; sure helps to have a manual. Generally, you press the learn button and a light comes on, then press the code on the remote once or twice (depending on the model) for it to learn the code or by whatever means they use. Chamberlain/Liftmaster learning transmitters require that you press and hold the button on the remote first, press and release the learn button while continually holding the button on the remote, and then release the button on the remote to program it.  And you do this individually with each remote or each button on the remote.  Learning receivers usually have a limited number of remotes that are able to program into them.  Usually they allow up to 8 total transmitters and keypads, some higher memory receivers can support anywhere from 18 to 250 code rolling remotes. To clear a rolling code opener receiver, you just press and hold the "learn" code button until the led indicator light goes out. Again, you might get lucky finding information from the manufacturer's website for programming.

The GDO track is torn loose from the door header; how do I repair that?

There has to be a reason it is torn loose, most likely because it was installed incorrectly. Also could be that the door is not balanced. Look at the motor mounts inside the motor box to see if they are ok; many times if the track is torn loose, the motor mounts are also damaged. If there is inside damage, it is best to get a new GDO.

If you have solved the damage problem and if you have the manual, that should tell you what to do. If you need to reinforce the header where the track was fastened, use a piece of 3/4' plywood or even a solid piece of lumber. Fasten it securely to the header and proceed from there. If the bolts or lag screws are torn out of the door, repair it somewhat the same way.

If you have a wood sectional door, fasten the reinforcing piece of wood from the top to the bottom of the top section to add some strength to it. Same deal with a metal angle on a metal door.

Opening/Closing Problems

Door goes to floor and bounces back up:
How do I make the down force setting? Manual is gone.
Door won't close; light beam sensors seem ok:
GDO won't open the door:
GDO seems to operate randomly:
Door closes but won't stay down:
GDO works ok but the light is erratic or off:

Door goes to floor and bounces back up:

Check that the door is balanced properly; disconnect the GDO from it and operate it manually. If ok, then set the up/down force and limit switches. Try the down limit first and set it so the door almost closes, then ease into fully closed position. You may have to set the down force as well, and you want to check that for safe operation anyway. If the settings just don't work, there is probably a malfunction on the circuit board. See notes about lightning damage for replacing the circuit board.  

An old chain drive GDO may be almost impossible to set correctly, Try lubricating the chain and if that doesn't help, consider replacing the unit with a screw drive model.

How do I make the down force setting? Manual is gone.

The usual method is the get the GDO limit settings correct first, particularly the closed position. Then lay a 2x4 flat on the ground and set the down force so it causes the GDO to reverse direction when the door hits the 2x4, Some sources say to use a rolled up newspaper instead of a 2x4.

An old chain drive GDO may be almost impossible to set correctly. Try lubricating the chain and if that doesn't help, consider replacing the unit with a screw drive model.

Door won't close; light beam sensors seem ok:

Usually the light beam sensors show a steady light when they are correctly aligned; pass your foot in front of one of them and see if the light flashes. If so, they are almost certainly ok. You can also test this by pressing and holding the wall push button. Doing this overrides the safety beam sensors and safety feature preprogrammed on your circuit board. Then check door balance with the GDO disconnected from it, and check GDO operation with it disconnected. If while closing your garage door hits an unbalanced portion of the rails, it will stop and reverse.

Sometimes a short in the wall button wiring or wall push button prevents the door from opening or closing.  Try disconnecting the wires FROM THE MOTOR UNIT, and test the opener with your remotes. This same short can also be found in the safety beam wiring usually caused by a pinch, cut, or frayed wire. 40% of all safety beam sensor problems are caused by faulty or shorted wiring.

If replacing the safety sensors does not fix the problem, try replacing the machine's circuit board.

GDO won't open the door:

Disconnect the GDO from the door and check door balance; then check that the GDO works without the door attached. If all seems ok, the up force adjustment probably needs to be set.

If your machine is making a "humming" or "buzzing" noise, there is a good chance that the capacitor has blown out and requires replacement.  To test this, you should be able to disconnect the door, open it manually, reconnect the door to the carriage assembly, and close the door using the GDO.  The capacitor is only used to give the machine enough power to initially lift the door.  Does not use the capacitor to close.  Other signs to a blown capacitor is white secretion physically coming out of the capacitor.  Get the MFD (microfarad) number range off the capacitor and the voltage (usually 220 volts, possiblye 330.) and check our replacement capacitors for the brand of your opener.  For Genie machines, the humming could also be a defective transformer on your circuit board. You will get the same symptoms above. Try replacing of your transformer, if that does not fix the problem, it could only be your circuit board that requires replacement.

For screw drive openers, if you hear a "grinding" or "screeching" noise, than the teeth of the carriage assembly or coupler assembly may be stripped.  You can check this by disconnecting  door from the carriage and disconnecting the rail of the machine at the header bracket (above the garage door) and checking the carriage assembly to see if it is stripped.  The coupler is mounting between the screw and motor unit. This is on the machine where the screw connects to it.

GDO seems to operate randomly:

Is it an old analog type? Look for dip switches inside the remote. If there are no dip switches, than it is probably rolling code, and anything could set it off, including overlying aircraft, a nearby radio station/frequency, CB radio, police radio, neighbor's GDO, car alarm radio controls, outside power transformer, power surge, etc.  First, try clearing the memory of the receiver if you have a learn button to program.   If you have dip switches, try changing the code to a different set of numbers to rule out someone else's GDO opening yours.  The frequency, however, you cannot change at all.  If the above mentioned fails, replace the receiver and transmitters all together with a universal receiver/transmitter conversion kit.  If all else fails, replace the GDO with a new one.

No, it is a newer GDO. Then a neighbor's remote is probably operating yours because the codes are the same. It could be a neighbor's remote for some other device as well. Change the digital code switches in both the remotes and the motor box, and the neighbor will probably be relieved as well. If it is a rolling code type, get out the manual and reset the rolling code sequence.

There could be a short in the wall button or wall button wiring sending a false signal opening and closing your garage door.  Try disconnecting the wall button FROM THE OPENER for a couple days to see if the problem continues. Then, replace the wiring, but if the problem consists; replace the wall button as well.

If you have spare remotes or a defective remote lying around, remove the batteries.  They could be sending a signal to your opener causing the door to opener randomly. Seldom, a remote that is becoming defective will send random signals to your opener.  You will notice this happening only while you are at home and that remote transmitter is nearby.  Try taking the batteries out of the remote while you are at home to see if it is a defecting remote sending random signals.

Door closes but won't stay down:

Disconnect the GDO from the door and check that the door is balanced. If so, reconnect it and set the down limit adjustment. Then set the down force adjustment. You want it to reverse if there is something in the way, but it may be set too sensitive. Make sure not to overset the down limit adjustment, because you will get the same problem.  This is a common occurence with Stanley GDO's that use "learn up/move up" and "learn down/move down" buttons to program limits.  Getting these settings just right on an old chain drive GDO can be difficult.

GDO works ok but the light is erratic or off:

Check the light bulb, of course. There is a thermal timer that holds the light on for 4 1/2 minutes after the door operates, and that timer is probably sticking. Try resetting the machine.  If your machine has a reset button, just press that.  If your machine does not have a reset button, then unplug and plug the machine back in.  If you are technically inclined, you might be able to fix it. Unplug the power cord, open the motor box and look for a small metal strip wrapped with fine wire; it is a bimetal strip with a heating coil. Use a fine file or piece of sandpaper to clean the contacts; black wet-or-dry paper is best. If you cannot find that bimetal strip, they may use a solid-state timer that you won't be able to fix. Replacing the circuit board is the answer in that case and it will probably be expensive. One neat solution is to use a separate motion detector light to solve the problem.