[MattMan]

I have a 25 year old Carrier (Model 28GS) A/C. It has been working fine until today. The condenser fan (outdoors) doesn't turn on, but I do hear the hum of the compressor. I believe the fan should be running all the time. I'm assuming the compressor is operating OK, even though it's not that loud. When I finally discovered the problem the freon tubes were hot. The fan spins freely and smooth by hand. I would greatly appreciate advice on how to check/inspect/replace the fan and/or the capacitor. I've not worked on the compressor/condenser assembly before. Should I just automatically replace the fan, capacitor, and switches if any? I don't know where the capacitor is located, must be under the housing. Also, the fan wiring doesn't have a visible connector to make the rewiring easy. Should there be? I have the top fan cover off, but can't remove the fan from the shaft easily. I'll have to find a wheel puller just to get that off.

Thank you very much in advance... MattMan :rolleyes:

[MattMan]

I should have added that everything else seems to be working fine, except that the air in the house is not getting cool. Could it be a bigger problem than just the condenser fan not working?

Thanks again, MattMan

[labman]

The fan should be running when the compressor is. Do not run it without the fan. It could be no more than a bad capactor, but I do not have time right now to explain checking it.

[MattMan]

By the way, the compressor probably ran (not continuously) for 5 or 6 hours before I noticed the problem.

Ok, I took off the side panel and found the electrical items as follows:
1. Capacitor
2. SuperBoost (brand name) relay and hard start capacitor. Has 2 black wires emanating from an attached cap that go to the main capacitor. This is not original equipment. Could have been in place for at least 5 years, probably 10 years.
3. Relay/switch
4. Some small round device with 3 wires leads (2 red and 1 black). One red wire goes to the relay.
5. Delay on break timer.

All the wires have connectors at their endpoints so part replacement would be simple. I don't have a problem replacing any or all. Probably should replace the capacitor and hard start compressor capacitor. What does the additional capacitor booster imply about my system? Will I need it with a new normal capacitor?

What do you think?

The date printed on the big capacitor is 1976. Ha! The whole house needs to be remodeled, 2800 sq ft worth, YIKES. I suppose a new HVAC system will be in order in a couple of years or less just for efficiency purposes and implied dollar savings. Well any comments are very welcome. Thanks again,
MattMan.

[labman]

Those big capacitors can be nasty. First step on any system with capacitors is to short them out. Use a plastic handled screwdriver. Touch a blade to one terminal of the capacitor and pivot it to touch the other. Do that with each one. Mid range Multimeters do not work well checking capacitors. Best thing is a good one with a capacitor checking function. Follow directions. With a cheap analog meter, put it on ohms and connect the leads while watching the meter. The needle should swing toward 0 initially and slowly creep back to infinity. Most air conditioners have a double capacitor in one case. It is almost more quick to check both than identify the one for the fan. If the motor turns freely and does not look obviously burned and the capacitor checks bad, likely it is bad and may well be worth replacing even on such an old unit. An HVAC dealer or an electrical supply house may be the best place to check for a new one. Just take the old one in and let them match it up. I am not sure about that SuperBoost (brand name) relay and hard start capacitor. If it is bad, try removing it, and see if starts without it. Otherwise, maybe a friendly supply house will help you.

[cottontop]

About how much $ ae the big anf small capasiters?