This is a little off site topic but I thought I’d post it as I had trouble tracking down the information. The condenser fan motor on my AC unit went out. THe sympton was the fan that sits at the top of the outside unit wasn’t spinning but the compressor was on. With the AC off the fan was hard to spin by hand, or rather a stick, I value my fingers. These fans should be freely spinning and free of friction under normal off conditions.
Obviously it needed to be replaced.
First a disclaimer for our sue-happy society -
WARNING!!! This information is for informational purposes only. Serious harm or death could result if you attempt to perform these repairs without proper training, preperation and equipment.
Okay with that said I didn’t find it all that difficult to replace the motor. Google was my friend when I ran into situations like the wires were different colors, there were more of them than I started with and the old fan was sharing a capacitor with the compressor.
I undid the sheet metal screws holding the top of the unit, the part that the fan is attached to and lifted it up and checked the data plate on the fan, writing down all the information, horsepower, voltage, amperage, speed, everything. Going online I found that these fans (mine was 1/4 HP, 1100RPM) typically run $70, the most recommended brand was AO Smith. Oddly enough the slower speed 850 RPM quieter fans cost considerably more.
Quotes to have a HVAC professional come out and replace it run from $400 to $1000 and research online seemed to bear those prices out based on people asking, “They only replaced a little fan and it took a few minutes, did I get screwed for $500?”
Given that little difference in price this became a no brainer to try myself. Let me state I have no experience with HVAC equipment at all.
I had my lovely wife pick up a replacement motor from Grainger. They’re not supposed to sell to the public but the counter man asked her where she worked and as it turns out her employer has an account there so they were able to sell it to her. There was some *wink wink* going on as in the guy knew he wasn’t really supposed to sell to her but a sale is a sale so he did.
She was also my Tool Monkey and emergency standby to call 911 if I managed to electrocute myself. Highly recommended to not try these things by yourself in case you accidently brush up against the hot lead on a capacitor with a sweaty arm.
WARNING!!! Remember to pull the fuses! Mine were located right next to the units and there are also circuit breakers you trip.
Fan in hand along with the necessary capacitor I removed the old fan, clipping the wires to get it out easier. The old fan had three wires, Black, Yellow and Brown, (Current, Current, Capacitor). I removed the fan blade, it was easy just loosen a set screw in the hub where the blades attach and slide it off.
Next I disassembled the side of the unit, the big non-finned side, taking out the outer cover piece I was then able to open the actual junction box.
Inside I found the old fan’s black and yellow wires going to the junction bar attached with spade connectors. I removed those, noting where they were attached.
WARNING!!! Capacitors can hold a charge, in fact that’s what they’re supposed to do. These things can still shock the everloving crap out of you and even kill you. I only had the crap shocked out of me obviously as I’m still alive to write this. Treat this thing with utmost respect, use rubber gloves and don’t touch it if you don’t have to.
The existing capacitor was a big one and handled both the fan and the compressor. It’s what is called a Split Capacitor I think. It had one ‘hot’ or yellow lead leading to the power strip (the big junction bar where the live current comes in from the house and gets split up among the various leads). It had one blue cable leading down to the compressor and a brown wire leading to the fan.
Since the new motor has 5 wires, its own capacitor I pulled the brown wire from the old capacitor and tossed it. You have to leave the yellow and blue (or whatever colors you might have) attached so your compressor will continue to work. The one for the fan is actually marked Fan on the capacitor by the way.
Unfortunately the new motor fan leads were too short to reach so I ended up using wire nuts to splice the old fan’s black and yellow power leads to the new fans black and purple power leads. I then plugged those back to their original locations on the junction bar.
The two brown leads from the new fan went to the new capacitor, one on each side. It makes no difference apparently which one goes where but remember I’m not a trained HVAC person and maybe I just got lucky, I had a 50/50 shot of getting them right regardless.
I then zip tied the new capacitor into the unit so it couldn’t accidently shift around and short out. Obviously some metal clamp and screw mount would have been better but I had no such thing.
Next came to mounting the fan. The replacement fan has screws so that it can be mounted either face up or face down depending on your preference. I needed it face down and I would bet that most of them do. These were way too long and I had to use a hacksaw to come them in half so the acorn nuts that hold it to the fan mount would screw all the way down.
The ones on the bottom were also way too long and I used a pair of vice grips to crush them off as near to the motor as I could. Vice grips were faster than hacksawing and I didn’t need to save the threads at all.
The ground wire that came with the new fan was short and there was only one place that I could see to put it. Over one of the fan mounting screws so it would be grounded against the unit’s case. I removed the paint to make sure it had a good solid connection.
I then tested the conditioner to make sure it worked and voila it did. Except it was running backwards. But luckily they thought of that and there was a little white plastic plug thing on the motor that you can pull apart, spin 180 degrees and plug back together to reverse the motor. This accomplished and voila, it was working 100% correctly.
Then I screwed everything back together and it’s worked since. And I saved a minimum of $340 dollars and spent an hour of my life.
Now that I know what needs to be done I don’t see this taking more than 20-30 minutes. I had to stop and research the changes in coloring on the wires and sealed it up once and then decided to go ahead and shorten the underside screws as much as possible. Technically I sealed it up twice and forgot to put the side piece in first which you can’t attach after you put the top back on. So I wasted a lot of time unnecessarily.
WARNING!!! Attempting the above yourself may result in you killing yourself. Please use utmost caution when playing with electricity.
