I replaced the fan motor on my AC unit, and it was recommended all over to replace the contactor at the same time. I had a single contractor (where only one leg of the 240v is switched) but I did some research and found out that most AC contractors that run their own business only stock dual leg contactors to save room on their truck.

Some manufacturers state that there is some bleed current that goes though the single leg to keep the motor slightly warm. At least on my model, that is impossible because there isn't a neutral to return that bleed current. Switching a single leg is electrically the same as switching both, unless current is being returned via ground (which in almost all cases is not allowed via code). My AC unit doesn't even have a ground electrical connection. If there is a ground connection, it is to 'earth' via the metal supports that hold up the AC unit in the concrete wall.

My unit has been running a few days on this, and had no issues with the contactor. The holes lined up with the old one, just had to unscrew the old one and hook up the new one after pulling the main disconnect.

GREAT PRICE

Works great! I replaced my OEM 30A single pole contactor in my central air condensing unit with this one. A 2-pole contactor is a little safer in protecting against shock if a serviceman was to inadvertently miss disconnecting the unit before replacing components and helps guard the unit against lightning damage. What the A/C manufacturers saved by installing the simpler, cheaper contactor certainly does not counter the shortcomings the single pole presents over time. Make sure you select the correct control voltage! This one is 24volt.

This replaced an OEM Payne 40Amp contactor. I've never fixed an air conditioner before, but when I took a look at the insides, it didn't look like it would take a rocket-scientist to figure out the problem and remedy it. I was right. A contactor is known as a "relay" in the rest of the non-HVAC world. That's what it looked like to me: a classic low-voltage circuit pressing together contacts for a high-voltage circuit. It was exactly that, and this unit did exactly that, replacing the OEM relay easily.

It isn't completely like the OEM contactor. The mounting holes are in a different place, necessitating drilling a couple of holes to mount using the screws from the original contactor. Also, the high-voltage connector lugs aren't exactly like the OEM: the original one had two screw-in contacts for the supply-side wires, and then two screws supporting a wire with a lug on it for the supplied-side. This unit is screw-ins on all four corners. I simply clipped off the lugs on the supplied-side, stripped the wires, and screwed them down. The other wires used crimped-on connectors, and these simply clipped right onto the the lugs of this unit. The last difference is that the relay connectors for the 24VAC control on this unit are north & south on this relay, rather than both on the "west" side like the OEM. So this unit isn't exactly like the OEM, but the difference is insignificant and doesn't affect operation at all. Time will tell how well this unit holds up. If I get 25% of the life the OEM had, I'll be more than happy.

This was a 10-minute job to replace the contactor (relay) to get my air conditioner working again. The previous one was sticking and would not pull in to close the contacts; the last time this happened I think it cost us $140 to have it replaced (I attached a picture of the failed one, this one is identical.) There is not much weatherproofing for the electrical components so this stuff is bound to have a shorter life.
This has a full set of connection options for spade terminals or screw posts that should work in any situation, and is DPDT so both legs of the power connection are switched.

Just make sure to turn off the power before you do this!