Yammer Dan Posted March 18, 2015 Share #1 Posted March 18, 2015 I had a Central Pneumatic 21 gallon 3 HP working /5 HP Peak Air compressor in the garage. Not the greatest Brand I know but did great for what I needed. Thing is after this last cold spell. Don't know if cold had anything to do with it. But it sat for about a month without running. Shouldn't have been anything unusual?? When I started to fire it up it just hummed. I waited til it got good and warm outside and tried again thinking cold could have something to do with it. It cycled about a 1/2 dozen times and just quit sitting there and humming again like the motor was trying to turn compressor and couldn't. I checked everything I could and came down to this. It has a Start Capacitor and a Run Capacitor. My thoughts were it was trying to start but wouldn't run. Now to the reason for this thread. If I am right??? I can't get the parts for the thing. It is about 4 yrs old and parts nowhere!! Is it just junk or can I replace those capacitors with something else without breaking the bank. It was a 150 buck compressor and looks like new. I hate to toss it. Not much to be said for Harbor Freight if you can't get parts for their JUNK!! Link to comment Share on other sites More sharing options...
scuff Posted March 18, 2015 Share #2 Posted March 18, 2015 I just went thru the same thing, could be the start capacitor, I got one from Grainger for ten bucks, pull your old one off and read the specs find one on Grainger with similar specs and try it. It didn't fix mine. My prob was there is a centrifical switch inside the motor on the end of the shaft with two small springs, one of my springs broke and came off, wouldn't the the switch work properly and engage the start circuit, you have to take the motor apart to see if this might be your prob, for ten bucks wouldn't hurt to try the start capacitor first, youtube start capacitor or electric motor repair lot's of good vids to help you out. Link to comment Share on other sites More sharing options...
Yammer Dan Posted March 18, 2015 Author Share #3 Posted March 18, 2015 It will start but only run for about a second. I'm thinking Run Capacitor?? Link to comment Share on other sites More sharing options...
Hummingbird Posted March 18, 2015 Share #4 Posted March 18, 2015 did you isolate the motor - take belts off ? Link to comment Share on other sites More sharing options...
oconeedan Posted March 18, 2015 Share #5 Posted March 18, 2015 First try plugging into a different outlet. If there is a weak connection anywhere, it will do what you are describing. If it does, you may have a weak gfi, or minimal capacity on that circuit. Compressors draw a lot when starting. Link to comment Share on other sites More sharing options...
Flyinfool Posted March 18, 2015 Share #6 Posted March 18, 2015 First take the belt off and see if the motor spins freely and see if you can turn the compressor by hand. Motor should spin free the compressor will have some resistance to turning by hand. If either one does not turn you know where to head next. Some one has to ask the silly obvious question, when you got it did you put oil in the compressor crank case? Is there still oil in it? Link to comment Share on other sites More sharing options...
Yammer Dan Posted March 18, 2015 Author Share #7 Posted March 18, 2015 Yes it has oil. It is direct drive. I am using a extension cord on it but it is a 12 gauge one. I had a 16 gauge on it for a long time and it ran fine. Can spin it by hand fairly easy. It will start and sound as a compressor should for about 2 seconds and then slows down til it just turns over very slowly and stops and sits and hums. I was thinking Run Capacitor just by the name of it. It has a Start and a Run Capacitor. It seems to try and start just won't run?? Link to comment Share on other sites More sharing options...
scuff Posted March 18, 2015 Share #8 Posted March 18, 2015 I would try run capacitor they're cheap, worth a try, from what I was seeing on youtube a lot of probs came down to just have to clean things up inside the motor i.e. electrical contacts and grease/replace bearings. Link to comment Share on other sites More sharing options...
Peder_y2k Posted March 18, 2015 Share #9 Posted March 18, 2015 The involved systems are...... Unloader valve (mechanical) Start capacitor Crossover switch (mechanical) Run capacitor Also possible is a failed armature bearing causing armature to field coil contact. Pete, in Tacoma WA USA Link to comment Share on other sites More sharing options...
Yammer Dan Posted March 19, 2015 Author Share #10 Posted March 19, 2015 I would try run capacitor they're cheap, worth a try, from what I was seeing on youtube a lot of probs came down to just have to clean things up inside the motor i.e. electrical contacts and grease/replace bearings. I think that's where I'm at if I can find a capacitor that will work. There are no parts for this thing. Stopped at Lowe's today and they have a very nice deal on a pancake with tools. What should I be looking for? Pressure it will maintain while working I know is important. I would like to use paint gun. What does it take to operate these??? Been a little over 40 yrs since I set up a gun. Don't remember what it took to operate it. Link to comment Share on other sites More sharing options...
djh3 Posted March 19, 2015 Share #11 Posted March 19, 2015 The new spray guns are HVLP (hi volume low pressure) My old gun I think I need to run 60psi or so. The new one is like 20psi operating press. I think I have the same compressor your having problems with. I might be able to find the manual andparts listing and you can try to order parts. I was just on harbor freights site and could look at all the manuals. At the back of them they have a parts listing. If you do decide to go the pancake route, I recomend plumbing the 21 gal tank up so you can use it as a storage tank along with the pancacke one. As it certainly will not have enough air to run much. Link to comment Share on other sites More sharing options...
Hummingbird Posted March 19, 2015 Share #12 Posted March 19, 2015 I just looked at craigs list wv and there are tons of compressor available I found a new Campbel-Hausfeld 5hp 120 gallon upright near me a few weeks ago - $600 I had to drive a couple hours Link to comment Share on other sites More sharing options...
friesman Posted March 19, 2015 Share #13 Posted March 19, 2015 Quick question after I tell something I had happen to my compressor. I loaned my compressor out once and it wouldn't run when I got it back, and did exactly as yours does. After wracking my brain and checking things over I found that the loanee had turned off the valve that allows air into the tank so the air had no where to go and the pressure sensor would shut down the compressor. So,this might seem like a stupid question but, ..is your valve open? Brian Link to comment Share on other sites More sharing options...
Yammer Dan Posted March 19, 2015 Author Share #14 Posted March 19, 2015 I FOUND IT!!! Started to take apart and take capacitor to parts place and try to match up with something. djh3 they say parts no longer available. Pulled on wiring to try and unplug capacitors and started loosing smoke!!! After I fixed short against frame it works but still don't shut down as it should. Itstead of just stopping when it gets up to pressure it slows down very slowly til it comes to a stop. Never did that before I don't think?? When it got up to pressure it was set for it just cut off al at once. Now it sounds as if straining to keep running before shutting down. Couldn't be good. Something on the settings I have gotten out of whack maybe?? Link to comment Share on other sites More sharing options...
Yammer Dan Posted March 19, 2015 Author Share #15 Posted March 19, 2015 Got that fixed too!!! Cranked pressure setting on tank back up and it shuts down as it should!!! Feel a little dumb not finding problem when it started but it was a strange one. If you have a Harbor Freight Compressor pull that plastic cover and look at melted plastic you have under there. Get rid of cover and melted plastic!! Just remember compressor gets hot but covering it up like that will trap heat and make the thing overheat!! Link to comment Share on other sites More sharing options...
Flyinfool Posted March 19, 2015 Share #16 Posted March 19, 2015 At least it is back to running. Now you can go back to being a blow hard....... Link to comment Share on other sites More sharing options...
mrsteve Posted March 19, 2015 Share #17 Posted March 19, 2015 Harbor Freights Chinese exporter seems to have many products with unavailable replacement parts, try getting the latches for their tag a long trailer. I was told by two stores that they are not available. Link to comment Share on other sites More sharing options...
scuff Posted March 20, 2015 Share #18 Posted March 20, 2015 Nice to hear you fixed it, instead of giving up and throwing things away, I feel like too many ppl just don't wanna bother and throw too many things away these days. Link to comment Share on other sites More sharing options...
djh3 Posted March 20, 2015 Share #19 Posted March 20, 2015 I like mine. It has server me well and I hope keeps on going. When I first got it I wondered about the beltless type drive and the motor being all covered up and such. It does blow a lot of hot air out of the cover around the motor if you use it alot like to run impact or air ratchet etc. I sprayed a trailer and some race car parts back when I got it. I quickly found out it dont hold quite enough air on demand. so I have a portable air bottle plumbed up so I can use it in line. Link to comment Share on other sites More sharing options...
Yammer Dan Posted March 20, 2015 Author Share #20 Posted March 20, 2015 Yeah that bugs me scuff. I don't give up too easy but it gets me that you can't get parts for it. I think I would have tried another capacitor before I tossed it but wasn't sure how to match one up to it. Glad I don't have to!!! Link to comment Share on other sites More sharing options...
Yammer Dan Posted March 20, 2015 Author Share #21 Posted March 20, 2015 I was on the right track. It was the run capacitor wire that had shorted!! Link to comment Share on other sites More sharing options...
Wrench Posted March 20, 2015 Share #22 Posted March 20, 2015 I have had one of these for about 6 yrs and it's done a good job for my needs. I had to replace the pressure switch a couple of years ago but that's it. Be careful ditching the plastic shroud, it directs air across the compressor and motor to help cool them off, (don't ask how I know). I also have a H/F HVLP gun that my son used to paint some parts on a car he had, plenty of air for that. Link to comment Share on other sites More sharing options...
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