How to troubleshoot window air conditioner?

Window ac throws breaker:
The first thing I look for is a broken compressor wire. A lot of times the wire will come off one of the clips and touch the compressor. That is a pretty easy fix. If the connections on the compressor all are ok and the compressor overload checks good (has continuity) then the next thing you look for is a swollen or shorted capacitor. If a capacitor will hold a charge then it most likely is ok, but if it is shorted internally it could explode when being tested, so I first make sure it is not shorted. I use an analog meter. The needle should jump slightly if the capacitor is good but if it shows continuity (the needle goes straight across and stays) Then that bad boy IS what the problem is. If a capacitor is open it is bad (but it won't throw the breaker). If the capacitor is ok it should just make a analog meter hop, reverse the leads and it should hop again. After you have made sure it is not shorted you can briefly apply 120 volts to the cap for just a second and then short it across anything with good conductive property's. If it is good you should hear an audible pop when you discharge the cap (if it is a fan cap the pop will not be as loud). Careful you don't discharge it on yourself or someone else. LOL I Am thinking the control switch is bad (shorted contacts internally) If the switch is ok then I check each component for short to copper on the unit. Anything that is shorted to the copper is the problem. I check all 3 pins on the compressor one at a time and none of them should be shorted to copper. If any of them pins on the compressor are shorted to copper(ground) then the compressor is bad. The fan could throw the breaker if one of its wires were shorted but that is highly unlikely.

Compressor won't run but the breaker is ok:
The first thing I check is for a broken wire
or an open capacitor
I check the cold control for continuity. If any of these are open then the compressor won't run but the fan will.

Compressor runs but fan don't:
Most of the time it is a bad fan motor but it could be anything from an obstruction holding the blade to a bad switch. The cold control would not stop the fan even if it was bad. The energy saver switch could though.

Window unit runs fan and compressor but does not cool:
This might be a low freon issue but how to tell if the freon is low? Here is a simple way to tell if you have enough freon. Cover the intake evaporator with a piece of cardboard and if after 10 minutes or more you have frost all the way back to the compressor then you do not need any freon. Most of the time you need to clean the coils. Remove the ac and take it outside for a good cleaning OR use no rinse spray if you can't move it. Acid is best but any soap will do. Just remember to cover up the fan motor good and do not get water on the controls. I have a high pressure nozzle that pushes a lot of the junk out on it's own. Just a piece of tubing that is pinched at the tip to force the water through. Real high tech. LOL After cleaning that bad boy up let the unit sit all night to dry if possible or all day anyway. Use a brush to remove the gunk first and then spray on some acid coil cleaner (non-acid no-rinse if inside the house) Rinse it well. LET IT DRY. If the motor has any moisture in it it will DIE!. Oil the motor using Zoomspout oil from ace hardware $2

Hole in window unit freon gone bye bye:
Well you need to locate the hole and clean around the area real well with sand cloth. To solder the hole their needs to be zero pressure in the system. Use 15% silver solder and use at least a Mapp gas torch or a "B" acetylene tank. Propane gas torch won't cut it. Oxygen Acetylene torch is even better. Heat up the area till it turns red and let the solder flow over the hole. Let er cool down. Shoot some dry nitrogen into the air conditioner to check for leaks. Bubble test. Lets talk about air in the system. Air is bad! Get air inside the system and freon is gonna find it and make ice. Ice blocks the flow. So pull a good deep vacuum on the system. I connect my red hose to the vacuum pump, yellow to the freon tank (valve on tank closed), and blue to the window unit suction line (that is the fat line coming out the compressor). This minimizes the chance of air getting into the sealed system once you get it vacuumed out good. Shut down the vacuum after a few minutes and watch the gauges. If the negative pressure does not drop quickly then most likely you have repaired the hole. Continue vacuuming out the unit for an hour or longer depending on how bad that hole was. Remember the longer you sweep the system the less likely a blockage or restriction gets in the lines. Close all valves and watch for drop in pressure. If the needle falls to 0 you have a leak. If it is a real slow leak it may take some time for the pressure to drop. So wait a while, go get some coffee and come back later to make sure she holds. Next open the freon jug, open the blue hose, and allow the unit to equalize. Do not open the red valve connected to the vacuum pump ain't no need it has done it's job. Check for leaks. I use a halide torch to check for leaks. If you are rich you might want to spend a chunk of money for an electronic leak detector. But hay if you was rich you probably would not be reading this. LOL! A halide torch is a simple rig. It connects to a propane bottle and has a rubber tubing attached to a burner with a window in it. Run the opposite end of the tubing slowly around the patch and look for the flame to change colors. If it does you have a leak. If you feel their are no leaks, open the suction line valve and open the freon tank, let it equalize then charge the system slowly to around 70 PSI. Do not exceed 70 psi. Around 60 psi start checking your amp draw to make sure your gauges ain't fooling you. Shut er down. Check your work once more for a leak. Pressure can cause it to leak if the repair is not sound. Qualified individuals only should attempt this but it is interesting as to how the process works and the equipment involved.

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