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Re: How to test capacitor
Watch out for those caps.you use the ohms setting ,may have to go to higher setting in ohms,but take your probes place on cap terms.the cap will read closed for a few seconds then go open,then reverse the probes and do again same result.if only open then may be bad,if your meters reading fine.i have only ever used a regular meter in all the years gone by.God bless,tom
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Hello, it is possible that the capacitor is bad and must be changed. You can test it by using a ohmeter, if the numbers on the meter ramp up and down then the cap is good, if not then it must be replaced.
This unit uses a dual run capacitor. There is no start capacitor involved.
The dual run capacitor is possible weak, also check all the electrical connections for tight fitting connections with can cause motor/compressor overheating. To test a capacitor properly you need the proper test meter capable of reading uf readings(within 6% of the stated rating on the capacitor) "C" common to "F" fan and "C" to "Herm" terminal, the higher rating for compressor and the lower for the outdoor fan. [(example= 25/3uf 370v) 25uf=compressor, 3uf=fan motor.]
The motor could have or not have a capacitor. You will be able to know if you can look at the wiring diagram which will be on the unit under the case, or disassembling the electrical compartement. The capacitor will more than likely be in the electrical compartment. It will look like a battery, and will probably be a 3 post capacitor. The fan will be connected to "common" and "fan".
To check the capacitor you will need an ohm meter. Unwire the capacitor on the fan and common terminals, marking where the wires go before you pull them off. Take the leads of the ohm meter, turn the meter to its highest ohm setting and touch the two posts with the leads. If the capacitor is good, the needle of the ohm meter will jump up, and then back down. If the ohm meter does nothing the capacitor is open, if the ohm meter needle jumps all the way over and doesn't come back down, it is shorted.
The blower motor could be bad or the motor run capacitor may be bad. If you have the proper tools you can test the run capacitor yourself and replace it.
***CAUTION***Anytimeyou are working on or around electricity you run the risk of shock and ordeath. Please consider consulting an expert before you open an electrical panelor appliance.***CAUTION***Capacitorshold a large electrical charge and will discharge upon contact with your skin.This is enough to stop your heart and cause death. If you are not confident ofyour abilities around these devices then please leave any testing or repairs toa professional.
The capacitor is inside the unitand you have to remove the cover to see the inside of the electrical compartment.You will need to discharge the capacitor before you start working around it. Todo this take a screwdriver or other long metal tool with an insulated handleand cross both terminals on the capacitor to ground. You then remove both wiresgoing to the capacitor terminals, which on fan motors are typically brownwires.
Capacitors are rated in MicroFarads (marked by a µF symbol) and have a voltage rating as well which istypically 370 volts or 440 volts. Youmust have a multimeter that can read micro farads to check a capacitor.
You do that by placing one probeon the one terminal and the other probe on the other terminal and it shouldread the number of the rating, for example if your capacitor is rated likethis: 7.5µF then the fan rating should read 7.5µF (seven and a half MicroFarads). If the reading is more than 6% lower than it is supposed to be, thecapacitor is weak and needs replaced. If you read 0 (zero) then the capacitoris bad and needs replaced. Take the old one with your to match up at your localhvac supplier.
A typical motor run capacitorrated at 5 µF +-6% at 370 Volts AC
The problem could be the capacitor for the compressor motor or the compressor motor. Use a multimeter with the capacitor test function to check it or take the capacitor to a heating and air supply and they can check it for you. If the capacitor looks swollen then it is bad. If the capacitor is good then use an ohmmeter to check the compressor motor windings. Connect one lead to common then the other lead to Run then Start, reading the meter when you connect the lead. The capacitor is a common failure.
The compressor is probably tripping on high discharge pressure due to the slow fan rotation. That can be caused by a weak capacitor or the fan motor failing. The capacitor can be checked with a multimeter that has the capacitor check function. The capacitors are inexpensive but the fan motor will be another story. You should also check the voltage going to the fan motor.
The fan motor uses a capacitor to turn the motor and if the capacitor is bad the fan won't rotate.If you are handy you could remove the electrical panel and change the capacitor and it will work fine again.I have tested these fans by simply turning the unit on and spinning the fan blade by hand!!! if the fan operates then the capacitor is bad!!
If no blowing air is coming out to your ac or evaporator fin,your blowing fan is not working.There are several factor to check qualified electrician or ac techician should do this.If you have knowledge on electricity and motor control,beside you should have clamp ammeter to use in trouble shooting of ac electrical circuit.Unplug your ac If there is an opening of blower fan of your ac mostly the top cover open this one locate the wire connection of blowing fan take the color and size.Open the terminal box below the control panel of ac and locate the wire of blowing fan.Check how many leads make sure to make sketch where it was connected from low,medium, and high there is coded color on it,discannect from the terminal, using clamp ammeter set to ohms probe setting R10 check continuinity of winding motor start at common lines(mostly balck color) of one test rod and the other to starting line(mostly red color)take and read the resistance if has a higher resistance your motor is burn out, also with the running line w/c has multple line for speed.If resistance complied to your motor rating or good,If not or burn out replace fun motor.Check your capacitor,doing this set your ohmeter to a higher resistance,connect one red test rod (+) one terminal of capacitor and one black test rod on (-)the other terminal the pointer will deflect steady to higher resistance then reverse the connection of the test rod,the pointer deflect again to higest resistance it will go slow backward setting to zero if you got this result your capacitor is good.But if it does not go set back to zero your capacitor is short.Replaced capaciter.