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The Pressure’s On

balloonPositive Pressure Issues

Sometimes doors are required to perform conflicting functions simultaneously.  For example, in order to comply with the American Disabilities Act a particular door may be restricted to a door closer that requires as little as five pounds of opening force.  This same door may be required to lock automatically without fail.

One solution could be to use a non-hydraulic, motorized power operator (automatic door opener) instead of a standard hydraulic closer.  Since many non-hydraulic power operators do not depend on a spring for closing force it is possible for them to have an ADA compliant opening force and also exert a closing adequate to close and latch the door.  Most power operators that fit this description must be installed by AAADM certified installers.

Without the magic fix of the non-hydraulic power operator, all a door technician can do is fine tune the door so that it swings perfectly and is perfectly balanced; fine tune the locks, hinges and door closer to peak performance under the opening force restriction; and pray there isn’t a positive pressure or wind issue.

One caveat:  deprived of electricity, a non-hydraulic power operator will neither open nor close the door.

Positive pressure HVAC operation is a prime example of how the intended function of a door can be impeded or prevented by the normal operation of building infrastructure.   Positive pressure in a building is accomplished by using the HVAC system to add air from outside the building to the air that is already in the building.  As with a balloon, the added air pushes outwards in all directions.  When an exterior door is opened, air flows out through the open portal, acting as an invisible barrier that keeps outside air out.

Unfortunately positive pressure acts like a constant wind pushing on the inside of the exterior doors.   Since almost all exterior doors swing out, the net effect of positive pressure HVAC on exterior doors is that of blowing to doors open and/or preventing them from closing.

The non-hydraulic power operator idea discussed above can usually solve the problem, but I have had some success adjusting door closers to compensate for positive pressure situations.  I have found that a slow swinging speed followed by a fast latching speed will often accomplish the mission.  This solution, however, can create other problems such as creating a wider time window for unauthorized persons to enter while the door is still shutting, for example.

I have found no reliable fix for an opening subjected to positive pressure that must comply with ADA reduced opening force requirements; however, since positive pressure on out-swinging doors inherently reduces opening force, there is some hope.

In the best of all worlds, door hardware technicians and HVAC technicians work together to coordinate positive pressure ventilation needs with security and ADA compliance requirements.

Excerpt from Tom’s article “Butcher, Baker, Door Hardware Technician… ” published in the February 2015 issue of Doors and Hardware Magazine, magazine of the Door Hardware Institute.

The Obsolete Mortise Lock

Nothing lasts forever.  Like manufacturers of other mechanical devices, lock companies periodically update their products to be consistent with current technology.  They do this to make better, safer, more reliable products, and also to remain competitive in the market place.

Sometimes these new, updated products are backwards-compatible with older models of the same brand, sometimes not.   In the case of mortise locks I can say with some confidence, mostly not.   One cannot replace a Schlage K series mortise lock body with an L series and expect the trim to work.  The same is true of the newer Sargent 8200 vs. the older 8100 and the Yale 8800 series vs. the previous 8700 series.  As these older locks age and must be replaced these differences can become a problem, since the existing trims and cylinders on site may not be usable with the new lock bodies.  And there are still plenty of these older lock bodies out there.  Case in point, although the Yale 8700 series was discontinued in 2006, one facility I know is filled to the brim with these mortise locks.

Although I foresaw that they would not be able to use the existing trims with their new locks I failed to anticipate that the existing cylinders would also be incompatible.  But they were and here is why.  On the left the cam that works with the Yale 8700 is in the process of being removed from a Medeco small format interchangeable core (SFIC) housing.  In the first picture below, the correct cam has been installed.







In the second picture you can see that the new cam is not only thinner than the old cam, it’s also slightly longer.  There is no way that old cam is going to work.  Luckily, on a Medeco SFIC housing the cams are interchangeable, unlike most others on which the cams are permanently attached.

Please visit my friends’ site:

Now I’m waiting to hear about the other SFIC housings on the job that have their cams staked on. But one cluster at time, eh?

The Wrap-Around Door Reinforcer

4CW2A wrap-around door reinforcer is a metal sleeve that slides over the door at the lock prep to conceal damage and/or reinforce the door.  They are a quick and handy solution when wood doors are damaged by forced entry and are often installed to strengthen new wooden doors against forced entry attempts.

In my experience a wrap does not really deter forced entry, but it does limit the damage done to the door.   I have found that when wood doors equipped with wrap around door reinforcers are burglarized, often only the wrap and the lock need replacing, not the whole door.   As with all door security hardware, if your lock is installed in a wrap-around door reinforcer and your neighbor’s lock is not, a would-be burglar may choose to break into your neighbor’s place instead of yours; however, this hypothesis is dependent on the highly dubious notion that a burglar is behaving rationally.  If the person were behaving rationally they would not risk their freedom and personal safety breaking into to somebody’s home to steal  their iPad or PC and selling it for chump change to their drug dealer.

Another benefit to using wrap-arounds is that they can act as a drill guide for lock installation.  Be careful, however, not to let the hole saw chew up the wrap.  Also, especially with stainless steel wraps, be sure not to let your drill bind up with the metal at high speed.  Injury would be likely.

Wraps are typically used on wooden doors, and while it is possible to use them on hollow metal doors, they never seem to fit quite right without a fight.  It seems that hollow metal doors measure exactly 1-3/4 inches thick whereas wood doors tend to measure closer to 1-11/16 inches.  Variations in door thickness affect the way a wrap will fit (or not fit) on a door.

A wide variety of wrap-arounds have been created to accommodate various locks and conditions.  Don Jo Manufacturing currently carries the largest assortment, and if a new kind of lock by a major manufacturer emerges, they are pretty quick to design a wrap for it.  To get the right borewrap for your application you need to know:

  • Door thickness
  • Size of the wrap you want
  • Diameter of the lock bore
  • Backset
  • Finish
  • Through-bolt holes (yes or no)

(see illustration)

Standard door thicknesses for wraps are 1-3/8 inches and 1-3/4 inches.  Some models of wraps are available thicker doors.   Wraps come in a variety of heights, but height is usually determined by the kind of lock the wrap is designed for and the backset.  See the illustration for bore, through-bolt hole and backset details.

For other wraps you may need other dimensions.  For example, Don Jo makes a number of wrap-arounds for interconnected locks and these (naturally) have two bores cut in instead of one.   If you need a wrap for a mortise lock you may have to change the trim on the lock to make it work, or you might have to drill lever, cylinder and thumb turn holes into a blank wrap to customize it to the lock you have.  See my warning about hole saws and stainless steel above.  I earned myself sprained fingers that way once.

I used to joke about certain doors that they could use a door sized wrap.  Then some enterprising individual actually brought one by.  The idea didn’t go anywhere, as far as I know, but it was a good concept:  one wrap covered the door completely in sheet metal and another covered the frame.  Still, at that point why would one just buy a hollow metal door and frame?

And that about wraps it up.

Schlage CO and AD Series Mortise Lock Parts

Schlage AD Series

Schlage AD Series

This just goes to show that there is no substitute for field experience. In the quest to provide the best service to his customer, this locksmith went past my advice and the advice of factory tech support to find the best solution.

The locksmith inquired about a replacement latch for a Schlage CO200MS mortise lock. I called Schlage Tech Support and they said that there were no replacement parts available for that CO-200 Series mortise lock chassis; that the entire mortise chassis had to be replaced for a hefty sum and I relayed this info to the locksmith. The locksmith, however, knew that Schlage advertised that the CO series locksets incorporated the Schlage standard L-series lock chassis “for durability and dependability.” Based on this, the locsksmith took a chance, went to the parts list for the L-Series mortise lock with the same function and ordered the replacement latch. He reports that is identical and works fine.

Good to know! One can assume that many parts from the L Series mortise lock with the same function will work in all AD and CO series mortise lock bodies. Like I said, you learn something new every day.

Thanks for stopping by.

What Is A Pullman Latch?

comparisonA Pullman latch is a type of exit device latch. The leading edge of a Pullman latch, the part that hits the strike first as the door closes, is a ramp.  The back of the latch, the part that rests against the strike to keep the door latched shut, is rounded.  When the Pullman latch comes into contact with another object it retracts automatically.  It is a simple, spring-loaded mechanism.

Some rim exit devices have Pullman latches, but most concealed and surface vertical rod exit devices do not.  Most vertical rod exit devices have a main latch that is shaped like a Pullman latch but also has an additional piece that looks like a kind of separate little latch, or auxiliary deadlatch.  This part interacts with the mechanism of the latch to keep the top latch retracted until this separate piece hits the strike as the door closes.  Then the main latch pops out and locks into the strike.

Latch release extended position.

Latch release extended position.

This latch-and-release design top latch is used by many manufacturers as the mechanism that holds both top and bottom latches in the retracted position while the door is open. That way the latches do not make contact with the surfaces of the door frame, floor or threshold.  When the top latch release makes contact with the strike it releases both top and bottom latches.

The photo to the left shows the latch release fully extended and the latch fully retracted.  This is the state that this type of latch is in when the door is open.

The Pullman latch is most often used with less-bottom-rod (A.K.A. top rod only) vertical rod exit devices when they are to be used with an electric strike.  The normal latch-and-release design is incompatible with most (if not all) electric strikes. Electric strikes that are compatible with Pullman latches are said to have Pullman keepers.

Sometimes Pullman latches are used as the top and bottom latches on vertical rod exit devices because they operate more quietly than standard latches.

Pullman latches are not fire rated and are not for use with fire rated exit devices.


Illustration of Pullman latch and Pullman keeper. Whereas the locking surfaces of electric strike keepers designed for use with cylindrical or mortise locks is perpendicular to the door frame, the Pullman keeper is at a 45 degree angle to the frame, creating an angled recess to accommodate the unique shape of the Pullman latch.

Hardware Preparedness

Preparedness for the Commercial Door Hardware Installer

One of the most time consuming aspects of hardware installation is travel to and from the job.  In a perfect world, the installer knows in advance everything they will need, but as we all know, the World of Hardware is not a perfect one.   Often there is no opportunity to survey the job beforehand and the information given by the client is often either sketchy or nonexistent.   As a result, travel time to and from is often doubled or tripled by the necessity to ‘go back to the shop’ to pick up the parts needed to complete a given job.  A certain amount of travel time is billable, nevertheless your customer is not happy paying for it, trust me.

While it is virtually impossible for a hardware or access control installer to be always prepared for every need, here are some items that go a long way toward helping to reduce travel time that results from a lack of parts.

Generally Speaking

The first rule of hardware preparedness is to pay attention.  What kind of hardware does your customer have, and what do they have that tends to break?  If your customer has a building full of mortise locks will swivel spindles, best keep a few of those spindles on the truck because you know they are going to break in the middle.  If your customer has entrances with Doromatic 1690 or 1990 concealed vertical rod devices, you’d better stock a few pinion cams because you know the teeth are going to break off of them.  Whenever you repair anything that looks like it’s poorly made and notice there is a quantity of it on the property, best carry what you need to fix it.

If you are doing a lot of work for a client and they have a particular kind of lock, be sure to stock a few.  The property manager will be impressed when you triumphantly produce one from your service vehicle in the nick of time.


You know what fasteners you often find missing in action.  Undercut flat Philips head 12-24 1/2-inch self tapping hinge screws, for example.  In an emergency they can double as ANSI strike screws.  Collect those 6-32 3/4-inch combination machine/wood screws from tubular and cylindrical lock latch and bolt fronts.  They can double as screws for a mortise lock armor front if you cut them short.   For aluminum doors it can be very handy to carry some 10-32 x 2-inch flat head Philips machine screws, and its always good to have a few universal mounting tabs around just in case.

Other Stuff

On the electrical side it’s always good to have a SPDT relay, one each of a 12vdc and 24vdc 1-Amp plug-in power supply and a 4-1/2 x 4-1/2 4-wire electric power transfer hinge in satin chrome are all things that one tends to find oneself wishing for on the job; the Securitron TM-9 timer module sure does come in handy sometimes; on the lock frontier it’s always good to have a few cheap replacement cylinders for emergencies; and a full surface reinforcing pivot hinge can be a life saver sometimes, though because they are handed you do have to carry both hands for the full prophylactic effect.

In addition to these common sense items there are a couple of products that can save a parts run, too.

LCN 4040XP

The 4040XP in the RW/PA configuration (by the LCN Door Closer division of Ingersoll Rand) is a non-handed door closer like many others that can be installed in either regular, top jamb or parallel arm mount.  Its adjustable spring tension makes it a perfect choice for doors that require a lot of force to close due to wind or other conditions, or for an ADA compliant opening that must open with minimal resistance.  If the installer carries the closer and the 4040-18, 4040-18PA and 4040-18TJ drop plates, they will be able to install the 4040XP on almost any door.  The most popular finish of the 4040XP is 689 aluminum.

HES Electric Strikes with Faceplate Options

Hanchett Entry Systems (HES) has greatly advanced the concept of the modular electric strike since the company was founded.

  • The HES 1006 is field selectable for 12 or 24 volts DC power input, and with an optional Smart Pac line conditioner you can use anything from 12 to 32 volts AC or DC.   A variety of available faceplates for the 1006 enable the strike to accommodate virtually any lock.   Carrying a 1006 body with one each J option, K option, KD option and KM option faceplates and one Smart Pac will allow the installer to fill the need for an electric strike for 95% of all storeroom function cylindrical and mortise locks where the installation involves a hollow metal frame.
  • The HES 5200 is field selectable for 12 or 24 volts DC power input and any power input from 12 to 32 volts AC or DC with a Smart Pac.  Unlike the 1006, the 5200 is field selectable for fail safe or fail secure.  Since the 5200 has a three quarter inch keeper depth it will accommodate a mortise lock in a pinch, but really the 5200 is for use with cylindrical locks in hollow metal, wood or aluminum frame applications or for aluminum storefront door applications that include the Adams Rite deadlatch.  I recommend installers carry one each of the 501, 502 and 503 faceplate options to be prepared for the majority of these installations.

There are many things I’m sure I’ve missed:  electrical tape, fifty feet of 18/2 non-shielded wire, really sharp wood chisels, batteries – all kinds of stuff.  But don’t worry.  You’ll know what it is the next time you have to drive back to the shop to get it.


How to Choose a Door Closer

To intelligently choose a door closer for your application you have to know certain facts:

  • Does the closer need to comply with ADA opening force guidelines?
  • Is the door an interior or exterior door?
  • What is the door width?
  • Will the closer be mounted on the push or pull side of the door?
  • Where on the door will the door closer be installed?  How much room is there?
  • Are there any special circumstances like wind, positive or negative pressure, etc.?
  • You may also need to know the door handing.

ADA Reduced Opening Force Guidelines

American Disabilities Act (ADA) reduced opening force restrictions are enforced by the Authority Having Jurisdiction in your locality.  In some localities or applications ADA requires a maximum opening force of 5 lbs. and in others a maximum opening force of 8.5 lbs.  Most closers on the market today can be field adjusted to comply with these restrictions, but to do so you need to have a door pressure gauge.

I am mildly acquainted with two door pressure gauges.  One is the model DPG by HMC and the other is the ADA/FG by LCN.  Apparently there are a lot of initials involved in door pressure.

Door closers are also available with reduced opening force meant specifically to comply to ADA standards.

Manufacturers usually print a disclaimer that says that a door closer adjusted to ADA maximum opening force may not have enough power to shut the door.  This is often true because perhaps recommended spring strengths for different applications are the result of perhaps a century of innovation.  Manufacturers know that a force greater than 8.5 pounds may be necessary to close a door.

Interior versus Exterior

When speaking about door closer closing force, we say that a door closer is of a certain size.  Door closer size does not refer to actual dimensions, but to spring strength.  Historically, door closers are available in sizes 1 through 6 – 1 being the wimpiest and 6 capable of exerting the strongest closing force.

A size 4 closer is usually recommended for an exterior, 3-foot wide door, whereas a size 3 closer is deemed appropriate for an interior door of the same dimensions.  The assumption here is that the exterior door is more likely to be expected to close a door against a wind or negative or positive air pressure.

Door Width

If you look at a door hung on butt hinges and equipped with a door closer from above, it looks something like this:

View from the Ceiling


You see from the illustration that the door closer closes the door by exerting force on a point about eight or ten inches from the hinge side of the door.  To see what this means, go to a door with no door closer.  Open it.  Now put your hand a foot from the hinge side of the door and push it closed.  Pretty difficult, isn’t it?   If your door was wider, it would be even harder to close from that point.  This is why door closer size – that is, spring strength – is determined by the width of the door rather than the height.

For a three foot wide exterior door, you would normally adjust your door closer to be a size four.  For a four foot wide exterior door you would adjust your door closer to be a size five.  Therefore, if you have a four foot wide exterior door, you had better buy a closer that can be adjusted to a size five.

Push or Pull?

Different arms are required for different applications.  On doors that swing out, where the closer is mounted on the push side, the closer is mounted in a top jamb or parallel arm configuration.  If it is mounted on the pull side it is mounted in what is called a ‘standard’ installation.  (There are other ways to mount a closer on the push side, but parallel arm and top jamb are the most common.)

See manufacturer’s literature for more information, or check out my article on Door Closer Basics.


If you have a glass and aluminum storefront kind of door, you may have a space issue as regards your choice of door closer.  If you have a hollow metal door with no window hung in a steel frame, chances are you will have no space issue.

You need to figure out what door closer will fit.  To do that, measure the space where you would like to install it and download installation templates or instructions from manufacturer’s web sites.  Check the dimensions to see if the closer you have selected will work or not.

Or you can measure your door and frame and consult a door hardware professional.

Special Circumstances

I have installed door closers in some fairly challenging environments.  One, for example, was on a four foot wide, eight foot high, two and a quarter inch thick mahogany and glass door.  In addition to the size of the door, the location was also challenging – right across Beacon Street from the Boston Common where the wind could race across the open ground and dash itself against the door to its heart’s content.  Also, the front of the building had settled over the century or so of its existence, and leaned decidedly inward.  The door opened inward, and, left on its own, would swing sedately inward to 90 degrees if not latched.

In other words I had to install a door closer that would close an extra heavy door, uphill, in a wind.  I actually got one that would do it about 95% of the time.  For this application I chose the most durable, powerful, adjustable door closer I knew at the time:  the LCN 4041.  If I did the same job today I would probably choose an LCN 4011 or a Norton 7500.

A big, beefy, versatile door closer is not a cure-all.  For example, sometimes the 4041 is just too big, or templated too close to the hinge.  The point is that you must look at all the details of your door before you buy a door closer – not only how it is made and its size, but its environment as well.


Easy Hinge Replacement

The easy way to replace worn hinges is to leave the door on its hinges while you replace them.

To do this:

  • You must replace the existing hinges with hinges of the same size
  • On a hollow metal door your hinges must match the hinge prep screw pattern
  • You must be able to open the door far enough so that you can reach the screws on the door leaf of the hinge with your screwdriver – typically you would need to open the door to about 100 degrees of opening

If any of these is not the case, stop right here and go get some help.   You will need to take down the door, put it in a door stand and replace the hinges one leaf at a time, the old fashioned way.

You will need:

  • A screwdriver that fits your hinge screws, most likely a number 3 Phillips head
  • A ladder
  • A piece of 1 x 4 pine between 2 and 3 feet long or similar piece of wood
  • Wood shim stock

If you are replacing hinges with the same size hinges and can open the door wide enough, go ahead and open the door to the degree of opening that best allows you to access all the hinges screws on both leaves.  Beneath the door place the piece of pine, and then between the pine and the bottom of the door stack shim stock until the door is fully supported by the wood.  If there is a closer on the door, the door should be resting securely enough on the wood shims so that the closer cannot close the door.  However, the door should be shimmed just enough to take the tension off the hinges – no more.  You want the hinge preps to remain as properly aligned as possible.

Once you have shimmed the door you can replace the hinges.   Start with the top.  Install each leaf with two screws only, not quite fully tightened.  Then move on to the next hinge, then the next, until they are all replaced.   When each hinge is in place with two screws in each leaf, tighten all the screws and try the door.  If the hinges bind or make noise, something is amiss and needs further adjustment.

If applicable, put masking tape over the strike plate and close the door.  Is the door happy to remain closed, or does it want to spring open?  If it wants to spring open, chances are the new hinges aren’t quite as thick as the old hinges and need to be shimmed.  Support the door with wood as before and inspect the hinges.  Both leaves should be flush.  If they appear to be inset, shim them out with very thin slices of wood that are the same height as the hinge prep.  Continue as necessary until when tested the door is stable when fully closed.


If the hinges bind or make noise, remove the screws from one leaf of the middle hinge and gently pry it out of the hinge prep.  Test the door again.  If the door still binds or makes noise, put the screws back in the middle hinge and try removing the screws from one leaf of the bottom hinge.   By this method you should be able to isolate the hinges that are binding and then look closer to determine the exact problem.

If, as you are working, you find that the hinge preps aren’t lining up so well, the door may have settled on the hinges – particularly if they are plain bearing, five knuckle steel butt hinges and they have been there a long time or had heavy use.  You may find that you have to shim the door up just a bit more to get the hinge preps to line up right for the new hinges.

If there is no possible way to get the hinge preps to line up right then you may be dealing with a deeper issue than simple hinge replacement.  Your best choice might be to put the old hinges back and then decide whether you want to replace the door, frame, or both, or whether you can use a surface mount continuous hinge instead.

Click here to read more about hinges.


Door Problems

If the space between the door and the frame is different at the top than it is at the bottom, you've either got a door problem, or you're going to have a door problem.

As a locksmith I was called many times to fix what the customer thought was a lock problem only to find that the problem was with the door, not with the lock.   “What’s the difference?” you may well ask, proving to me that you are no locksmith.  “Well,” I would smugly reply, relishing my brief moment in the spotlight of useful knowledge.  “I’ll tell you.”  And I will, too.


Hardware and doors age together and develop different and sometimes incompatible symptoms of aging.  Like people, doors are subject to the prolonged effects of gravity.  Things start to sag, and for a while you can tighten things up and slow down or even perhaps reverse the effects, but eventually Newton will have his way and what was put up will come down.  That is to say the door, suspended an eighth of an inch (ideally) above the threshold, will eventually come to rest on that threshold.  If left to the ravages of time it will eventually cut a groove in the threshold.

Locks, meanwhile, start having trouble finding their strikes.  (A strike is to a lock what a tunnel is to a train or the side pocket to the eight ball.)  Usually (but not always) the strike stays put, but the lock travels downward along with the lock side of the door.  Eventually the lock may not line up with the strike at all, but before that there will be friction between the bolt or latch and the strike, making the lock difficult and eventually impossible to lock and/or unlock.

Besides sagging, wooden doors may warp and door frames of any construction may move as the building shifts and settles over time.  These changes may also result in locks that no longer line up and do not work properly.

Diagnoses and Remedies

The Sagging Door

Looking at the closed door from the ‘pull’ side, it is often easy to see if it is sagging.  If the jamb has not moved and was installed correctly, it is perfectly square.  Ideally there will be a one eighth inch gap between the top and the left and right edges of the door and the frame.  If the door hangs at an angle to the frame, it is probably sagging.

Marks on this ANSI 4-7/8 strike plate show that the latch has traveled down as it has traveled through time because of gravity.

If a door is sagging enough, there will be marks on the lock edge of the door where it is rubbing against the frame.

Often this is because the top hinge is loose.  If you tighten all the hinge screws this may solve the problem.  On a wooden door and/or frame you may find that the screws for the top hinge are stripped – that is, the screw hole has become enlarged because the weight of the door has pulled the screw out.  The solution for this situation may be longer screws.  Be sure you replace the screw with one of the same wire size so it fits flush in the countersunk screw hole of the hinge.  Commercial hinges use a size 12 screw, but bring one of the screws to the hardware store to match it up if you have any doubts.

Many times longer screws do not solve the problem because the wood door is not solid would, but particle core or gypsum core, or the frame is shimmed out from the studs so far that that there is nothing for a screw less than five inches long to grab.  In this case it might be necessary to relocate the top hinge (not generally a good result), install an additional hinge or hinges above and/or below the existing top hinge, install a reinforcing pivot hinge at the top of the door, or replace all the hinges with a continuous hinge.

Damaged Hinges and Crooked Door Jambs

If hinge tightening does not solve the problem, the hinge or hinges may be bent or the door frame may have shifted.

Hinges are often bent when someone (who is not too bright) places a piece of wood between the door and the frame to hold the door open.  It is possible to bend a hinge back to almost its original shape, but when it is bent the metal of the hinge is fatigued and it will never be the same.  Since hinges vary by manufacturer, it is best to replace all the hinges if one is bent unless you can find an exact replacement for the bent hinge.

If the hinges are neither loose nor bent, the door frame may be out of alignment.  Use a carpenter’s square to check the corners of the frame and a level to check the legs and header.

If it is a three-piece, knock down hollow metal frame in a sheet rock wall, you may find an adjustment screw at about eye level on each leg of the frame.  These vary widely between door manufacturers, so see what kind of driver may be required to turn the adjusting screw.   You can experiment with the adjusting screw to see if turning one or the other either way has any desirable effect.  Sometimes the adjustment screws are not connected to anything that has contact with anything else.  In that case turning the adjustment screws will have no effect.

Hollow metal frames that are installed in interior sheet rock walls are often secured to the wall at the bottom of each leg with a screw.  If the floor has shifted beneath the frame so that one leg is now lower than the other, it is possible to remove the screws from both sides of the leg, gently pry the leg up off the floor a little and insert shimming material beneath the leg to hold it up.

Wooden Doors and Frames

Wooden doors and frames are generally susceptible to more movement than hollow metal.  In addition to sagging, there is warping, twisting and swelling that may occur.  Fortunately whenever finished wood rubs up against something, it tends to leave a mark.  These marks can tell you what the door is up to and help you fix the problem.

Unlike a hollow metal or Fiberglas door, you can plane a wood door down.  Careful, though:  make sure you iron out any hinge problems before you start to plane, otherwise you’ll plane, the door will sag more, you’ll plane some more, the door will sag some more – pretty soon you’ll have a big space between the frame and the door someplace and you won’t need a door viewer anymore because you’ll be able to see out the crack.

One has no choice but to plane a door that has swollen.  Plane carefully, a little at a time, and do your best to keep the door as square as possible.  After planing, finish the door with paint, polyurethane or varnish – especially the edges – so that it doesn’t swell again so fast.

This is not a complete list of door problems, but it is a good sampling.  I hope it serves as a starting point for you to solve your own.