KEISER AIR 250 (01) PDF Document

KEISER AIR 250 exercise machines provide infinite adjustable resistance, which can be increased or decreased by the user during exercise by means of thumb buttons at the hand grips. Resistance may be easily changed at any time during the workout. Resistance may also be set low during extension then increased prior to contraction for a higher resistance or negative exercise.

ALWAYS USE EXTREME CAUTION WHEN ADJUSTING RESISTANCE DURING NEGATIVE EXERCISE TO AVOID DAMAGE TO THE JOINTS, TENDONS AND MUSCLES.

When adjusting for a negative exercise, the correct resistance reading will appear only after returning the exercise arm to the rest position.

Each machine has a supply hose with a quick disconnect fitting plugged into a compressed air system. Air flows into the machine through this hose and through a filter. Pressing the increase (+) button allows air to flow into the cylinders, tanks, and processor box. The more air let into the machine the greater the resistance will be. The maximum resistance will be determined by the pressure available in the compressed air system; this should be 100 PSI. Moving the exercise arm from the rest position moves the piston in the cylinder. This compresses the air in the cylinder into the tanks. The air pressure against the cylinder piston creates a mechanical resistance. Resistance is lowered by pressing the decrease (-) button, allowing air to flow out of the machine and into the atmosphere.

The digital display will hold the resistance reading once set and will not show a change during exercise motion. An exception to this occurs when the user adjusts the resistance during the exercise (as in doing negatives). In that case, the reading will vary during exercise motion, but will show and hold the correct resistance the next time the exercise arm is returned to the rest position. The digital display will also show the repetition count. If the resistance is changed during the exercise, the display will skip a count until another full exercise stroke has been performed. Then the repetition count will resume.

For users who are extremely deconditioned and find that the lowest resistance is still too high, the resistance may be decreased below the normal minimum by pressing and holding the decrease (-) button while moving the exercise arms through the full range of motion. When at full extension, release the decrease (-) button and return the exercise arms to the rest position. This will create a vacuum in the machine and will counterbalance most or all of the weight of the exercise arms. In this condition the display will not show the correct resistance.

This maintenance schedule is the recommended minimum requirement for all KEISER AIR 250 machines. Failure to follow these instructions at the suggested intervals will constitute neglect of normal care as required by the warranty.

Follow these steps to diagnose the problem:

Is the machine’s quick-disconnect plugged into the air system?

If not, plug in the quick-disconnect.

Do all other machines work?

If not, check the compressor.

Does the machine work when plugged into another outlet?

If yes, replace the bad outlet.

Are any hoses kinked or damaged?

If yes, repair or replace the hose.

If none of the above solve the issue, check the valves.

Follow these steps to diagnose the problem:

Are the cylinder rods clean and lubricated?

If not, clean and lubricate rods (see cylinder servicing).

Are any hoses kinked?

If yes, straighten or replace the damaged hose.

Are all pivot bearings lubricated? (Note: Sealed ball bearings without fittings are lifetime lubricated)

If not, lubricate the bearings.

Are pivot bushings badly worn?

If yes, replace bushings.

Is the exhaust muffler clogged?

If yes, replace the muffler.

If none of the above apply, check the cylinder bore for proper lubrication.

If the pressure changes without the valves being operated, you should replace the valves.

The digital display is battery powered. When the batteries are approaching the need for replacement, the display will show “loba”, for low battery, instead of “off”.

To replace the batteries:

1. Use two industrial alkaline “D” cell batteries.

2. Access the batteries by removing the cover of the processor box fastened to the frame of the machine.

3. To remove the cover, pull or pry the sides of the cover outward to free the detent boss from the holes in the body of the box. No removal of screws is necessary.

4. Replace the old batteries with the new ones.

When the batteries have been replaced the display will run through a self-check flashing a series of numbers. Once the test sequence stops and the display shows “off” the equipment is ready to use.

If an air leak is suspected, first listen closely to the air hose connections. Leaks will make a hissing noise. Very slight leaks may be detected by dabbing soapy water on the suspected leak. (NOTE: DO NOT GET WATER ON ELECTRONICS.) Escaping air will make bubbles. If the leak is at the fitting, first tighten the nut no more than one-quarter of a turn. Test the connection again. If the fitting still leaks, the nut must be replaced.

To install a new hose, fitting, or nut:

1. Cut the tubing as close as possible to the nut. The cut must be clean and square.

2. Slip a new nut over the tubing.

3. Insert the tubing into the fitting all the way to the shoulder inside the fitting.

4. Hold the tubing in the fitting and slide the nut down onto the fitting. Tighten the nut as tight as possible with fingers, then one full turn with a wrench.

When replacing a component or hose using barb fittings:

1. Cut the tubing 1/2” away from the component to clear the barb ridges.

2. Pry the short hose section off the barb, being careful to avoid nicking or cutting the barb ridges.

3. Check the condition of the barb ridges. If they show cuts or nicks, replace the fitting. When replacing a barb fitting a thread locking compound (such as “Loctite 242 -Blue”) must be used on the metal threads to provide a proper air seal.

4. Push the end of the hose onto the fitting as far as you can.

Note: The urethane hose may be pried off the fitting without cutting the hose. The end of the hose will enlarge with repeated removals and will lose the ability to seal properly. If this happens cut 1/4″ off of the end of the hose and reattach it to the barb.

The feed hose is connected to the quick-disconnect using a barbed fitting. If the feed hose must be repaired, shortened, or replaced, follow the procedure outlined for BARB FITTINGS.

The filter on KEISER AIR 250 machines is an “in line” filter that cannot be disassembled. When the filter element is dirty, the element turns a bright pink or red. At that point, the filter must be replaced.

All filters have a directional arrow and must be installed so the arrow points in the direction of air flow into the machine. Always decrease the resistance of the machine to zero and unplug from the main air supply before starting service or repair.

CAUTION: IF THE FILTER BOWL IS CRACKED, IT MUST BE REPLACED IMMEDIATELY.

NOTICE: IF FILTER BOWL IS CRACKED, AN AIR LEAK COULD RUN THE COMPRESSOR CONTINUOUSLY, PUTTING EXCESSIVE WEAR ON THE COMPRESSOR.

TOOLS REQUIRED: 3/32″ Allen wrench, Standard screwdriver, Wire Cutters. (Read entire instructions first).

1. Unplug the quick disconnect on the supply hose and decrease the resistance to zero.

CAUTION: IF RESISTANCE IS NOT REDUCED TO ZERO AND UNPLUGGED FROM THE MAIN AIR SUPPLY BEFORE REMOVING THE +/- CAP, THE VALVE SPOOL MAY “SHOOT” OUT OF THE VALVE HOUSING.

2. Remove the +/- cap from the handle and pull the valve out using the flange on the valve. By pulling out on the thumb button, the thumb button spool assembly will be removed. Pull out until the hoses can be cut about 1/2″ from the bottom of the valve housing. Mark the hose connected to the barb on the side next to the two ball plugs in the side of the valve housing. This is the high pressure hose and must be correctly reconnected or the valve will not seal properly. Sometimes it is necessary to push the hoses into the exercise arm where they enter it from the machine frame to get enough slack to remove the valve.

3. Disconnect digital display wires from the thumb button plugs. If there are two on one valve, they may be reconnected either way. Pry the hoses off the barb fittings or cut each about 1/2″ from the end of the valve housing and pry the short piece off each barb. The decrease (-) valve has a short piece of hose on the barb that serves as an exhaust muffler.

NOTICE: DO NOT CUT ACROSS THE RIDGES ON THE BARBS. DAMAGED BARBS ARE AREAS FOR POSSIBLE LEAKS.

4. Replace the valve, pushing the high pressure hose onto the barb on the side with the two pressed in balls. On the increase (+) valve the second hose connects to the machine system. On the decrease (-) valve the short notched hose or muffler connects to the other barb.

5. Digital Display wires must be re-connected. It is essential that the electrical wires have enough slack so the connector is not pulled off if the hoses must be pulled in during installation of the valve.

NOTICE: USE CARE DURING INSTALLATION. DO NOT PULL THE CAP OUT ON A NEW VALVE AS THIS WILL REMOVE THE CAP-SPOOL ASSEMBLY AND MAY DAMAGE ONE OF THE “O” RINGS ON THE SPOOL. IF THIS OCCURS THE VALVE MAY NOT SEAL PROPERLY.

6. Replace each increase (+) and decrease (-) cap with the (+) or (-) symbol toward the user when in the exercise position. When in the exercise position, the increase (+) cap should be on the right side handle.

7. Reconnect the quick disconnect to the air system.

NOTICE: BOTH INCREASE (+) AND DECREASE (-) CAPS MUST BE SECURED IN PLACE. IF THE AIR SUPPLY IS CONNECTED WITH THE CAPS REMOVED AND THE THUMB BUTTON IS PULLED SLIGHTLY, IT IS POSSIBLE TO BLOW THE SEAL OUT OF THE VALVE.

TOOLS REQUIRED: Adjustable wrench, 5/16″ or 1/4″ Allen wrench.

1. Unplug the quick-disconnect from the air system and reduce the resistance to zero.

2. Remove the air hose from the cylinder. On machines with dual cylinders it is best to remove one cylinder at a time. If both cylinders must be removed, mark the cylinders and air lines to avoid mistakes during reassembling.

3. Remove the nuts and bolts holding the cylinder and clevis. Check the bearings in the tang end of the cylinder and the lever arm. If they are loose or worn, they must be replaced.

1. Put a drop of oil on the bearings and remount the cylinder. Tighten all nuts securely.

2. Reattach the air hose. Tighten the nut finger-tight, plus one-quarter turn. Plug in the quick-disconnect and check for air leaks. If the fitting leaks, tighten the nut another one-quarter turn. If the leak persists, replace the nut.

NOTICE: IT IS VERY IMPORTANT THAT THE CYLINDER ROD AND BORE ARE NOT SCRATCHED OR DAMAGED IN ANY WAY. DAMAGED CYLINDER RODS AND BORES ARE AREAS FOR POSSIBLE AIR LEAKS.

TOOLS REQUIRED: 11/16″ wrench or socket, Internal Snap Ring pliers, rag and MT-55 light grease.

1. Using the 11/16″ wrench, carefully remove the muffler from the end housing of the cylinder.

2. Clamp the tang of the cylinder in a vise or have someone hold the cylinder. If the ends of the snap ring are not visible, the end housing must be rotated until both ends are visible through the cut-out.

3. Pull the rod out 2/3 to 3/4 of the way. Squeeze the snap ring with snap ring pliers and pull on the rod to “tap” the end housing out of the cylinder.

4. Wipe out the bore of the cylinder with a lint-free rag and inspect for scratches or uneven wear. If found, a replacement may be needed.

5. Clean the piston and inspect for wear or damage. If any metal particles are found on the piston or inside the cylinder a replacement may be needed.

6. Clean the wear strip grooves and apply a moderate coat of “Hydrotex MT-55” light grease to hold wear strips in place during assembly. Lightly coat the bore, cup seal, piston and wear strips with MT-55 light grease. Carefully reassemble the cylinder.

NOTICE: OPEN END OF CUP SEAL MUST FACE AWAY FROM THE CYLINDER ROD.

7. Apply a very light coat of oil to the muffler threads and reinstall snug, but not tight.

8. Operate piston by hand through its stroke. There should be no stickiness or metal to metal contact.

9. Wipe the cylinder rods clean and coat them lightly with clean, SAE 30 Wt. Motor Oil, or with Silicon-based spray.

Cylinders are factory-adjusted and need not be readjusted unless the cylinder or clevis becomes loose or is replaced. While each machine is checked differently, cylinder adjustments are basically the same.

TOOLS REQUIRED: 2 large adjustable wrenches.

1. Hold the clevis in position with a wrench and loosen the lock nut.

NOTICE: LOOSENING THE LOCK NUT WITHOUT HOLDING THE CLEVIS CAN DAMAGE THE BUSHINGS, CLEVIS AND THE CYLINDER ROD.

2. Adjust the rod length as required.

3. Hold the clevis and tighten the lock nut. Watch the rod to make sure it does not turn while tightening the nut.

The mufflers on the rod ends of the cylinders should be replaced at any time cylinder problems are suspected. Removing the muffler and moving the exercise arm through its range will determine if the muffler is clogged. A clogged muffler will make the motion spongy or rough. Mufflers should be replaced every 12 months.

When replacing a muffler, coat the threads with oil, silicon lubricant, or “WD-40”, and reinstall snug but not tight.

1. Unplug the quick disconnect fitting from the air supply and reduce the resistance to zero.

2. Remove the screws in the clamps at both ends of the belt and remove the belt.

3. The belt has one side that is smooth and one side that is rough. Install the new belt so the smooth side lies against each pulley. Use “Loctite 242” on each screw and reinstall clamps.

4. Pull each end of the belt through its clamp about 2” and tighten the screws enough to hold the belt under light load. Reconnect the quick disconnect and slowly move the exercise arms through the full range of motion. The belt should remain taut when the exercise arms are returned to the stops. For those machines on which the hand grips can come together at full extension, extend both exercise arms simultaneously to their maximum position and adjust the belt length as needed to give thumb clearance between the two thumb buttons. Be sure to bring resistance back to zero before loosening clamps.

5. After making final adjustments to belt length, torque each “Grade 8” 1/4” clamping screw to 15-20 ft.-lbs.

1. Unplug the quick disconnect fitting from the air supply and reduce the resistance to zero.

2. Remove the screws in the clamp at the cylinder arm end of the belt and slide the end of the belt out.

3. Remove the single bolt and keeper washer from the pivoting bracket at the other end of the belt.

4. To install a new belt, fasten the single screw end first. For standard (non-range limiter) machines install the belt so the smooth side will ride against the pulley. For range limited machines install with the smooth side of the belt against the pivoting bracket. Note that the bracket is made with one mount surface almost in line with the pivot center. The belt should lie against that surface so it pulls straight through the pivot center. The outside of the belt should clamp with the keeper washer with the recessed side against the belt. Torque the “Grade 8” 5/16″ screw to 25-35 ft.-lbs. Be careful to keep the belt straight.

5. Route the belt over the pulley and under the clamp on the cylinder arm. Use Loctite 242 on the 1/4” and reinstall the clamp. Pull the belt through about 2″ and tighten the screws enough to hold the belt.

6. Plug the quick disconnect into the compressed air supply and slowly increase resistance to 10-15 lb. standing clear of any exercise arms that may be extended. Move the exercise arm through the full range of motion checking that the belt remains taut when the exercise arm is returned to the stop. If necessary, decrease pressure to zero and take up belt slack.

7. When the belt length is correctly set, go through the complete range of motion, observing whether the belt is tracking straight and clears the sides of the slot in the range limiter.

8. Once the belt is tracking properly torque each “Grade 8” 1/4” clamping screw to 15-20 ft.-lbs. If the belt will not track properly, you may need to seek service.

Tightness of nuts and screws should be checked monthly. Most screws should not be tightened any more than necessary to keep them from turning freely.

All screws must use self locking nuts to prevent loosening. Those, which thread into tapped holes (including set screws), must be retained by a thread locking compound such as “Loctite 242”. Screws, which bear on painted surfaces, will normally have a washer to protect the surface.

All high strength bolts should be torqued to the tabulated values to obtain maximum strength. Screws used for clamps must be tightened gradually so both sides pull in evenly. The cap of the clamp must stay parallel to the mating half so the screw heads bear evenly on the cap. Only once the cap has been securely snugged down should the bolts be torqued.

Note: When screws are installed using a thread locking compound (such as “Loctite”) torque to the lower value of the range listed.

When replacing screws use an equal or higher grade. Socket head cap screws must be non-plated to achieve maximum strength.

TOOLS REQUIRED: Drift punch and hammer

WARNING: EYE PROTECTION MUST BE WORN WHEN REMOVING SPRING PINS.

1. Look at the exploded view of the machine in the parts section and find the size of the pin.

2. Using the proper size drift punch, tap the pin into the shaft until the pin is completely out of the bracket.

3. Remove the shaft from the bracket and tap the spring pin through and out of the shaft.

NOTICE: ALWAYS REMOVE THE PIN FROM THE SHAFT IMMEDIATELY. ACCIDENTAL INSTALLATION OF A SECOND PIN WILL DAMAGE THE MACHINE.

1. Check the hole in the shaft to make sure the old pin has been removed. Check to ensure that the new spring pin will fit snugly in the hole in the shaft. If it is loose, the shaft must be replaced.

2. Assemble the shaft in the bracket.

3. Tap the new spring pin into the bracket until the end of the pin is flush with the outside. Be careful not to damage paint.

The 1/2″, 5/8″, and 1″ flange bearings must be lubricated every 3 months. Using SAE 30 Wt. Motor Oil, put one drop on the exposed portion of each bearing. Move the machine through its range to work the oil in, then wipe the area around it free of exposed oil.

1. Remove the old grip from machine and clean the handle with rubbing alcohol. Be sure not to get any rubbing alcohol on the thumb button.

2. Slide the grip sleeve onto the handle about 1/2″ past the thumb button.

3. Slide the grip end cap onto the end of the handle and position the set screw. Tighten the set screws while holding the cap all the way onto the handle. Those end caps with (+) or (-) should be turned with the symbol toward the equipment user. NEVER OVER TIGHTEN THE END CAP.