Air Conditioning - Condenser fan not spinning, compressor trying

5 yr old split Lennox unit. Noticed high temp in house. First checked interior fan - it was just recirculating room temp air. Then checked compressor unit outside - Noticed that the condenser fan was not spinning. Compressor appears to be humming, but no diff in temp on pipes. Opened service panel to check voltage across different connectors and definitely have voltage to fan & compressor from capacitor. Fan motor is very hot. I popped the lid off the unit, tipping it up to vertical to get a good look at the fan motor. Spun the blade just to make sure it was free and the fan motor engaged (look out fingers!). When I put the lid back to horizontal the motor immediately stopped again. Is this more likely to indicate a problem with the fan motor or with the capacitor? Any specific things I can check? Thanks for any help.

sounds like capacitor is the likely culprit, they are cheap replace that first. Be sure to discharge the capacitor before touching it and be sure to replace with the same size microfarad capacitor. If you have time post back results

Will post back tomorrow if I get the chance to work on it myself. It may still be under builder waranty, in which case I'll try to get them to do the service.

I was disappointed in my ability to identify my capacitor online using the compressor unit model number. The capacitor itself is pretty rusty/corroded on the outside - not sure if I'll be able to read anything from it even if I did take it out. Can anybody recommend a good online site for parts lookups (I've been unable to reach Lennox.com this weekend - maybe they'll be back online on Monday????).

Thanks!!

I have had very bad luck with dealers getting me the correct capacitor information, they are actually wrong about 25% of the time when they look it up, it is always best to match what is there, try really hard to read what is on the existing capacitor.

As a home owner you're not gonna have much success in getting parts for a Lennox usin their numbers. Like DNT said, just take it out and go to your nearest electric supply house, hvac supply house, or motor repair shop and they'll be able to get you what you need.

Short Version: It was the capacitor and I'm really going to wish I had fixed it myself...

Long Version: Since I still have time left on my home builder's 5 year comprehensive systems waranty I gave them a chance to succeed. They referred me to one of the big local HVAC service companies and asked that we have the service performed, pay for it ourselves, then fax them the invoice so they can review and reimburse me under the waranty, if applicable (WARNING SIGN!). I followed along, just in case it was a bigger deal than the capacitor. Got a next day service appt. The tech removed the capacitor and it did show evidence of "blowout" on the both ends (more on the bottom than the top) and apparently failed his capacitance test. He didn't have a dual 45/5 capacitor in the truck, so he "made" one by taping together a 45 and a 5 and bridging the commons ('nuther WARNING SIGN). Then he manufactured a new bracket to hold the pair in the unit and viola, cold air. In the process he did try to sell me on the benefits of an $84 hard start capacitor add-on (500% improvement in compressor torque! Yet another WARNING SIGN). I declined in hopes of keeping it simple for reimbursement from the builder. Will be faxing the bill back to the builder for possible re-imbursement (just barely under $200 - 75 for the visit, 125 for the custom capacitor configuration). Can't wait to see how this one turns out myself.

The way he did the cap will be fine but the price is a little high on the parts. But if you get reimbused it don't matter.