Fan/Condenser Fan Motor Replacment

Condenser/Fan Motor Repair for Air Conditioners and Heatpumps

Description: This is the procedure and information for replacing a condenser fan motor aka outdoor motor, fan motor,spinning thingy on an air conditioner. The specific unit in this example is a carrier brand ground level, split straight cool system. This procedure applies to almost every air conditioning and heat pump system on the market. It also applies to packaged system. This is a straight forward repair but some topics that will be covered in other pages; "Diagnosing a bad motor", "How to get the right motor", "Tried and true fan blade removal techniques" to name a few. Fan motor failures are not very common but do have a high probability of happening within the life expectancy of typical system. A intermittent fan can go unnoticed until the motor dies completely. A failed motor can act much like a bad fan capacitor. If the fan motor or the fan motor capacitor fails, it will cause the compressor to go out on high pressure. If you have high pressure protection it will shut the compressor off before it goes into by-pass. If you don't the compressor will go into bypass and run until it over heats. Now I have seen many compressors go through this process and survive but common sense says it shortens the life of the system every time it happens!

What does a repair like this cost:  The price of this repair varies a lot from region to region but even from repair man to repair man. A lot depends on the area you live in, the company, flat rate vs. time and material and many other factors. I have seen prices as low as $200 and as high as $1600. Fan motors for this repair are pretty inexpensive. A fan motor can be picked up for $40-$100 in most cases. The hardest part is getting the fan motor.  It is a great candidate for a do it yourself person or someone just looking to save a little cash.

 

 

Tools: 

    • Nut Drivers/Screw Driver like this one [img]/sites/default/files/driver.jpg[/img]
    • Wire Stripper/Crimpers [img]/sites/default/files/crimpers.jpg[/img]
    • Not required! Gloves I prefer mechanics gloves.
    • Not required! Volt Meter [img]/sites/default/files/voltmetersmall.jpg[/img]
    • Large crescent wrench
    • Optional: Penetrating oil such WD-40 or the like
    • Optional: Hacksaw or reciporcating saw with a metal blade

Estimated Repair Time: 30-60 minutes

Materials: 

    • Fan Motor
    • Zip Ties
    • Electrical Tape
    • Capacitor
    • Universal Mounting Bracket (not need for the repair)
  • Condenser CoilLocate your condenser aka the out door unit. Here is the one we are working on today. It about 10 years old. It is the builder put in so we can be sure it is not top of the line.
  • Disconnect Location Turn off off the disconnect.
  • It is a good idea to check and make sure their is no power to the condenser with a voltage tester or meter.
  • Here is our disconnect. It is a breaker type you man have the pull out type.
  • [img]../ter/image.jpg[/img]Turning of the breaker at the break panel is a good idea too. If I make the effort to turn off the breaker for the condenser for split units like this I turn of the air handler too.
  • Condenser Access PanelFind and open the access panel. A good clue if you air conditioning system has more than one cover. It is the one with the electrical warning sticker on it. Here is the one for this unit. It is held on by two screws but a trick to easy removal is loosening this top two screws too.
  • Location of screws on fan grillGain access to the fan motor. This procedure will vary some what from unit to unit. Some motors may even be held in with a mounting bracket.  The one is base mounted to the fan grill. Remove all the screws holding the grill down.
  • Fan Motor and Blade exposedI like to leave the base mounted on this type of system for the fan blade removal. Here you see the fan grill flipped over.
  • Caution: The fan blade spins as several hunderd revolutions per minute(RPM). Because of this, force applied properly is important. To name few things I have seen from hurried repairs or ones when brute force was applied or just plan lack attention to detail are as follows.
    • Bent or tweaked fan grill.
    • Bent or tweak fan blade.
    • Intentional (why I will never know?) or unintentional removal of the fan blade balance weights.
Now if you do tweak the blade or fan grill. I am sure you are thinking, how do I tell if I tweak it? What does it do? How can I fix it?
    • I am going to suggest if you tweak you know it most of the time. Say maybe, you get some kind of tool to apply torque or worse yet a hammer. For stubborn blade removals patience and finesse is required not brute force. If it looks bent, you bent it. If you lay the blade on a flat surface and the top of hub(where the set screw is see below) does make a line parallel to the flat surface then your balde is bent. There are other indicators to but I can't remember a blade I bent I wasn't pretty sure I bent. Sometimes you just get lucky.
    • What does it do if you try and run a system with a bent fan blade. When the fan is running(spinning at speed), does the condenser rattle and vibrate like it was going to come a part. If it does, you bent something or possibley knocked the balance weight off the blade. Most likely the blade is bent but maybe you knocked the balance weight off. If you can find it, put it back in the dust shadow blade. My advice, don't bend anything. Use patience and finesse.
    • How do fix.
      • You can try putting the balance weight back on in the dust shadow where it was originally located.
      • Try tweaking it back to original position. OMG, if I nickel for all the times I have seen this but it never seems to work well. Unit always has some kind of vibration just not as much.
      • Try moving the balance. All that comes to mind is good luck. Think how would I put balance weights on my tires; static or dynamic. It is similar.
      • But my recommendation. Buy a new blade!

    • Fan set screwFirst step put penetrating oil on the hub where the blade is located.
    • Second step, remove the set screw and for Pete's sake don't lose it[/b]. Where does that saying come from...
    • Now with this one it was not necessary but in a lot of situations the shaft protrudes past the hub. That protruding shafting is rusted. Use the sandpaper and sand that shaft until it shines with fresh metal. Now this may seem like common sense but if you are new you may not think about it. Since the shaft is round, put the sand paper around the shaft and pull it back and forth like your each hand. Similar motion to like running one of those eclipse machines at the gym. It will sand down in minutes even seconds.[/b]
  • If you follow the prior instructions, this part is usually pretty easy. Remember patience and finesse.

      • Fan motor with crescent on itPlace a your crescent under the blade, on the shaft.

    Size it for the flat part of the shaft. Now if I move the cresent the fan blade moves.

    • Why a crescent? Well because it is what I have found that works best for me. It is fast, they come invarious sizes (I like the 10").
    • What if the crescent wrench will not fit? Well get a thinner one. If you can't find one that fits, well you have to use something else. You can apply this technique with the crescent wrench above the blade on the protruding shaft but I find it easier when under the blade.
    • Can I use something else? Why sure, vise grips, channel locks, pipe wrench on and on. I recommend a crescent wrench.
    • Let me talk minute about fan blade pullers.  I have seen all kinds.  Some work well others not so well.  I have not had  much use for pullers.  I used many and seen many more.  I have never feel like they were worth the money.  This process works 99% of time.

Now the blade is off.  Cut the wires for the motor.  It is never a bad idea to make sure the power is off first.  I find myself double, triple and quadruple checking this right before I touch something that uses electricity.  Flip the fan grill back over.  Don't tweak the fan grill.  Loosen and remove the  fan motor mounting nuts  I use the crescent wrench but about anything works.  I keep these nuts for the new motor but they are not necessary for the install.

 

Here is my new motor next to the old one. I am replacing my OEM 3 wire motor with a 4 wire motor.  Click here to learn more about 3 wire to 4 wire motors.   

The motor I am installing is a brand new motor.  I am installing an extreme heat version since it is hot in the summer around these parts.  Click here Learn how to get the right size motor.  

It is good practice to always replace the fan motor capacitor with motor.  You will notice this motor has some extra wires.  It has the extra long wire (why it is called a four wire).  

You will also notice the yellow and orange wires.  If you flip these wires, yellow to orange instead of yellow to yellow and orange to orange, this will reverse the motor rotation.  Motor facing down, my rotation is clockwise so I changed the wires from yellow to orange.  

You may also notice the shaft on the motor is much longer.  We will cut this down one the motor is mounted to the grill and the fan blade is installed on the new motor.

 

Motor Ground wireI removed the green ground wire since my frame is ground but if the wasn't like in a situation where the mounting bracket has rubber vibration dampers between it and the frame you need to connect the ground wire.  

Motor Drain Plug locationRemove the drain plugs.  This is an often missed step.  It will not make the motor fail immediately but will shorten it's life.  There are plugs on both ends.  You only need to remove the ones on the pointing down.  

Mount the motor to the fan grill.  Notice the extra nuts on the back of the new motor.  Use this extra nuts to mount the motor on the fan grill. Mount the motor to the fan grill so the wires coming out of the motor are in the position as the old motor's wires were located.  Make sure the mounting nuts are tight.  You don't want the fan motor coming off 6 months down the road and damaging the coil which is a more expensive repair.  It sounds like common sense but I have seen it.

Install the fan blade on the new motor.  Now this is a mistake I have seen often.  The fan blade needs to be at the same height from the base of the condenser.  In this case the motors are approximately the same height.  Don't put the fan blade two or 3 inches down the shaft.  In this case to get it at the same height from the base of the condenser I needed it right up next to the when the shaft comes out of the motor.  

  • You ask why the same height.  It is so it sucks air through the whole coil.  I have seen it several times where the motor and balde is installed improperly and on hot days the system can't cool the living space(house, apartment).  The only problem is the motor installed is too tall or more often the fan blade is installed to far down the shaft.  Replacement motors tend to have very long shafts.  If the fan blade is half way down the coil, when it is running air will only be drawn over the part of the coil below the fan blade.  When this mistake is made, it often a very experienced technician to diagnose it.  What is more common is the recomendation for a new condenser.  I would say more often than not, it is not done on purpose.  The technician just does not know what the problem is just that it is in the condenser.  But with all this, even if done incorrectly it will most like cool your house with out issue just use more electricity than necessary.

Tighten the set screw on the flat of the shaft.  Not on the round part, on the flat part.  Again common sense, but I seen it done.  Make sure it is tight.  

When i went to install the fan grill, I noticed the new motor's shaft was hitting the compressor.  The shaft is too long.  It needs to be cut.  I used a sawall but you could a hacksaw blade or some other clever trick.  

Install the wire cover.  

Drop the wires through the access hole.  Mount the fan grill.  Notice I left the, orange and yellow wires out of the top.  This is poor practice since the sun will rot them given enough time.  They should be taped to the wire cover.  I went back and fixed it later.

Cap nuts

I put the old round caps on the bolts so they are not a hazard.  You can also cut them down but that too.  

Old Wire Connections

Now all we have to do is hook up our wires.  The two brown wires on my four wire to the new capacitor.  My cap is marked and the solid brown goes to the one marked FAN.  The brown with the white stripe goes to the terminal marked COM.  

The black wire to the black wire I cut and the yellow wire I cut to my new motor's white wire.  I cut them back and used wire nuts to connect them.  

Finished connectionsHere is the finished connections.  Now you may noticed I did use my old dual capacitors fan capacitor.  Well this is not a good idea in most cases but this is newly replaced capacitor.  I checked it and decided to the roll the dice.  However, I don't recommend this practice.

 

  • We are done now but some of the best advice I ever received was to measure twice and cut once. This applies here too. Double check all the wires are the connections are in the right place and where they are suppose to be connected. Verify all the connections are tight. I like to give each wire a little tug at the base of the connection to verify this. Quick tip: If the your spade connectors are loose, pull them off, pinch them down just a little with your crimpers and reconnect them. This tip alone can save numerous failures. Loose connections cause failures
  • ThermostatProceed to the the thermostat and turn it on so it calls for cooling. It is the same process you go through when you find your house to hot and you want it cooler.
  • Contractor pulled inIf all has gone well, the contactor should be pulled in. If your contactor is open, it would look like this. It is usually accompanied with a slight hum or buzz but not always. Most systems have a delay before turning the condenser on so be patient.
  • As soon as it comes on there are couple of critical checks.  
    • Is it blowing air out of the top?  If not, pull(or flip breaker) the discconect and reverse you rotation wires.  The yellow and orange ones.  We got it wrong.
    • Is the amp draw on the motor below the motor rating?  If not, you have the wrong/bad capacitor or more than likely the wrong motor.  Will it last if it is just a little bit above?  NO!
    • Is it vibrating badly?  See above but you most likely tweak the blade or possibly the fan grill.
  • In my case, all check were good.  Air blowing out the top, amp draw under rating and no vibration.  Operation success.
  • Pull the disconnect.
  • Put the condenser cover back on air conditioning condenser.
  • With the contactor pull in, turn the disconnect back on. The air conditioner will come on and run.

You just saved big bucks!