My air conditioner wont kick on, it just buzzes a little?

Question

i replaced the blace braker box with the 4 wires running to and from it! i checked the power going to it! there was 244 on both end and 25 on the outer 2 plugs on the side! its doing the same thing it did with the old part in it! the unit worked fine last year!i have a wireless thermostat! when i try to spin the fan with the power on, nothing happens! i can feel it hum a little but other then that, nothin! please help! timeline is short! and its frickin hot outside! thank you for any comments!

Answer 1

Replace the fan motor. The windings have shorted out.

Answer 2

I think you are talking about the contactor relay --- the 2 wires on the side are the low voltage 24 volt coming from the transformer-- passing through your T-stat to the contactor --- which closes the points (contacts) and allows the 220volt to cross over and start the compressor.

OK ---------

In this wiring system(outside/condenser) you will have a 'capacitor" --- this can be a silver/round "thing" with wires plugged in to the top of it(terminals).You may have 1 capacitor with 3 terminal connections/wires coming out  --- , or you could have 2 seperate capacitors with wires.

Normally --- the capacitor is marked with its' ratings --- for instance >. 35/5uf .

The 1st number is for the compressor ----------A capacitor is required to start the compressor --- if bad , then the compressor may only "humm", or perhaps nothing at all.

The 2nd number is for the blower fan motor --- A capacitor is required to start the fan motor --- if bad , then the fan motor may only "humm", or perhaps nothing at all.

Both(either) may sit there and get hot --- if the capacitor is bad.

If I understand you --- the(outside) fan motor (condenser unit) is not working --- blowing air

You may have a bad blower fan motor , or the capacitor(5uf) is blown.

This would apply to the evaporator blower fan motor also(inside unit )

A capacitor boosts up the power to run a motor/compressor --- if it's bad --- then you may get a "humm" from lack of power to start it.

If this is the case --- then replace the capacitor.  

If this does not help ---then the blower fan motor needs to be replaced.

Now since the blower fan motor is not running ( and the compressor is running) --- you would think that the capacitor (3 terminals) on the "fan" side (5uf)is bad --- probably so ----.

A 35/5uf capacitor will costs you (depends)about $35 ---- but really all you may need is a single 5uf capacitor for the blower fan motor.

You will see on the top of the 3 terminal capacitor writing ---- Herm / C (common) /Fan .

The "Herm" could also be marked "M" --- for motor >> same thing.

To save money , in this case , you could buy just a single small 5uf capacitor for a few bucks ($4 -$5).

Then take the wire off the old capacitor (on fan)and push it on to the terminal(either side)on the new 5uf capacitor.

Then take a "jumper wire" with end connectors , and push one end on to the old capacitor on "C common" , and connect the other end to the terminal on the new 5uf capacitor.

What you are doing here is to replace the bad part(5uf side)of the old capacitor  using the jumper wires to the new one.

If your unit has 2 capacitors -- then replace the smaller one --- the smaller one may not be a 5uf --- it might be a 7,5uf , or a 10uf --- regardless -- this goes to the fan motor.

If you don't feel comfortable about using jumper wires  --- then replace the entire capacitor with the same ratings--- if it's a 35/5uf/370 volts --- 25/7.5uf/370 volts -- 40/10uf/440 volts --- use the same.

Capacitors can "hold" a electrical charge , and can give you quite a "zap" if you touch the terminals --- it's like a battery with a stored up electrical charge that will get you .

With the capacitor removed ---- you could use a insulated screwdriver to "short" across the top terminals by touching them . This will probably cause a loud , electrical "crack" and may cause you to jerk back a little.

Anyway ----- there you go.

With the 4th July upon us --- many stores will be closed and you will not be able to get any new parts for a couple days.

In this case then --- look around at old A/C units to salvage  --- if there's any around.

You can salvage a large capacitor and use the "fan" side of it only(if it matches) -- using jumper wires as mentioned.

Good Luck ---  Stay Cool .

                                            +++Spock+++

Answer 3

So you replaced the box mounted to the wall that holds two fuses???  If the unit was humming before doing this you probably wasted your time unless it was an old disconnect box.  

When you try to spin the fan will it spin?  Or is it stiff?  If it moves but you just hear humming, it could be the fan motor or the compressor that you hear.  Chances are you need to replace the capacitor, you need a special meter to read how much MFD there is, or you could go buy a capacitor which probably isnt going to be happening tonight.  They range in size, you have to get the one appropriate for your fan motor, too big will burn up the motor, too little still wont work.  Chances are it is a 3, 5, or 7.5 MFD capacitor.  This is a common problem for condensing units.  

The capacitor is a tin can looking thing inside the unit.  They could be round or oval.  They usually have two terminals on top.  If you see one with three terminals it is called a dual capacitor, if the top is popped up, the capacitor is done, and you need a new one.  If it is a dual pay attention to the writing next to the terminal which will be "C" "F" and "HERM" make sure you match the wires or it will not work properly.

If the fan is stiff when the unit is on, then you need to replace the fan motor and the capacitor, chances are the motor is fried.  If you replace the motor, you need to get the one with the same HP and RPM, otherwise it may not work properly.  There are universal fan motors, if you dont know how to read a wiring diagram dont attempt to change the motor.

Most likely you condenser needs to be cleaned with chemicals that can usually only be obtained from an HVAC supplier, and no just spraying it off with water will not clean it properly, dust and dirt caught inbetween the fins will cause a decrease in efficiency and cause things like the capacitor to blow, the compressor to work harder and not last as long.  Make sure the unit can breath and nothing is around it like weeds, grass, or any house hold items as this will cause issues.

Remember to always DISCONNECT THE POWER WHEN WORKING WIITH THE ELECTRICAL INSIDE THE CONDENSING UNIT.

Good Luck

Answer 4

stop kicking it and turn the switch on