Air conditioner STILL won't work in an outlet that checks out okay. Help?
Question:This is part two to the question that I was helped with earlier today (thanks to all who answered). Part one was: I had power in an outlet but my 240V Air conditioner would not work when plugged in. I called Con Ed who had botched up some work a few months ago, they came, they blamed it on the last crew and they fixed it. My 2nd floor A/C works but my 1st floor still does not.
I ran the A/C by extension cord to the upstairs outlet. Plugged it on, it works. So I know the A/C is not faulty.
Next I bought a multimeter and tested the outlet.
Voltage is 240 which is where it should be.
Resistance is between 4.4 - 4.3 which the manual says is ok.
Continuity is OK according to the multimeter, in other words the multimeter buzzed.
I also measured diodes not knowing what that means but it came up OK. The manual says it should be 0.5 - 0.8, mine was 0.5.
So I'm stumped! I have the right voltage and everything else looks good. And I know my A/C is ok. Why won't it work?
Answers:
I answered here yesterday but today Im confussed so let me ask a question or 2. are you sure the unit is 240 volts I ask this cause you said you ran a ext cord to the unit.... 240 volt ext cords are few and far between even if you had a 240 volt ext cord where did you plug it in to get the power and the only place in a normal home is the cloths dryer outlet and dont tell me its gas. next with your ohm meter where did you take your reading and never never use a ohm meter or a volt/ohm meter in the ohm position with power on. what does your outlet for the ac look like is it like 3 slots at the 1 at the 10 oclock and 1 at the 2 oclock and one at 6 oclock position or it may have a 4th which is ground and usually is round or it may be a slot with a tab bent to the side. you can email me or maybe we could IM yahoo. your not stupid just learning and I give you that but there are things you can do and somethings you can get hurt by doing.lol hang in there BTW..a ohm meter in this case will only indicate a short circuit you can check the voltage by using your meter and select AC Voltage and use the 500 volt range and at the wall outlet place your red lead in the vertical slot (power) and the black lead (ground/netural) into the lower slot or hole and you should have indicated 110 to 120 vac if not that slot may be netural so check the other side with the red lead see if voltage is there if so that outlet is a 120 v outlet if you get voltage in the 120 range at both slots it would be wired for 240v
This is a 3-prong outlet right? Check and make sure that the ground at the outlet is good. Many 240VAC appliances have a safety switch that will prevent operation if the ground is not present or faulty.
Make sure that the round part of the plug is ground and that the 'blade' inserts are 240VAC between themselves. You should be able to measure 120VAC from each blade to the round insert or ground. Other than that I'd say call an electrician tomorrow.
Using the AC Volt setting on your meter, check and record voltage readings on all the pin combinations for the working 240V outlet.
compare this to the non working outlet. If there is a difference (more than a few volts) then pursue that difference either with Con Ed or an electrician.. If there are no differences, I am stumped.
A missing/swapped ground or neutral is highly suspect here, but kind of sophisticated troubleshooting. they could read correct on a meter, but newer AC/s might not power up.
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