After power cut, no cold air

[michaeljc70]

I accidentally shut off the power at the circuit breaker for my furnace (not condenser) while looking for the circuit for something else. The a/c was on.

After turning the power back on, my a/c was not blowing cold air and the unit outside was not on. I went back to the circuit breaker and the double circuit for the a/c condenser was not all the way to off, but not all the way to on either, like it had been triggered off.

I flipped it to ON and turned the A/c on. The condenser turned on (well, at least the fan on top of it), but no cold air. I also heard a surge every few minutes. I have always heard a surge when first turning the a/c on.

I repeated turning the a/c on/off from the thermostat and still room temp air. Even tried turning it to heat, waiting, turning it back to a/c.

Any ideas? Could cutting the power to the furnace but not the condenser have fried something?

[JWWebster]

You might have a burnt wire on the compressor. Sometimes a brief interruption can cause a terminal wire to melt. I would check for a fail compressor capacitor. Might be that the fan motr has a sep cap or that the fan side of the cap is ok. Could be a contact on the magnetic contator has been fried.
My page: https://sites.google.com/site/sublimeappliancerepair/ask-the-sublime-one-a-question/outside-condenser-blues

[haroldsappliance]

Time delay could be faulty. Power off and then right back on is not good, hence the time delay component. That is the purpose, as pressure equalizing on the system will allow unit to start with less labor. Locked rotor amperage is four to six times that of running amps. Excess amps are always converted to heat. A loose connection will pull excess amps and could eventually burn and over heat a compressor terminal.

[michaeljc70]

You might have a burnt wire on the compressor. Sometimes a brief interruption can cause a terminal wire to melt. I would check for a fail compressor capacitor. Might be that the fan motr has a sep cap or that the fan side of the cap is ok. Could be a contact on the magnetic contator has been fried.
My page: https://sites.google.com/site/sublimeappliancerepair/ask-the-sublime-one-a-question/outside-condenser-blues

After looking around on the web, I had actually taken the panel off the a/c unit and inspected the capacitor. It looked surprisingly new (unit is 11 years old). 

One thing that was a little "Burnt" was the thingy in the box on the side of my house. It is a metal electrical box and instead of a pull down handle, it has a cartridge like thing.  I pulled that out and it looked a little burnt and there was a little melted plastic on the box part.  I figured that probably isn't it as the unit has power and as I understand it, it either has power or it doesn't. 

[JWWebster]

That might be a barrel fuse. Be careful with that.

[michaeljc70]

That might be a barrel fuse. Be careful with that.

I looked up barrel fuse. It is something else.  It is rectangular and has a metal bar that pulls up so you can grab it and pull it out.  It appears that it just completes the circuit and there is no fuse or other parts in it.  I think it is just an alternative to the electrical box with the pull down handle to cut the power.

[JWWebster]

Got any pictures of it and the unit?

[michaeljc70]

These should give you a pretty good idea.  It is an Armstrong unit BTW.

I appreciate the help.  I know I most likely need to get someone out.   However, believe it or not, I am having 50 people over tomorrow for a party.  I thought if it is something small I can take care of, it would save me. It is supposed to be 93 here tomorrow.   

I have 2 units. 1 for the lower 2 levels and one for the upper.  I am probably going to blast the upper level tomorrow and hope for the best. 

[michaeljc70]

After looking at the pics closer, the purple wire looks a little burnt or at least dirty.

[JWWebster]

Red wire also looks burnt. Did you remove the cover on the compressor and look for burnt wires?

[michaeljc70]

No. I didn't really realize there was a cover on it.  Are you talking just the part where the wires go in, or is there a cover over the whole thing?   

Assuming there are a couple burnt wires, those would just need to be replaced?  Since the unit does turn on (at least the fan), it seems like only the wires going to the compressor are a concern?

[JWWebster]

Under that cover is 3 pins. Each pin is attach to motor windings. Their is a C or common wire connected to both the R run winding and S start winding. So 3 pins R S and c. Look for one of them wires to be burnt (it happens). Look for leaks around the cap and a swollen top. cannot really tell from the photo angle. Is that capacitor a dual one. cannot tell from photo. The Contactor is a 30 amp 1.5 pole with a 24 volt solenoid coil. I would remove the cover over them 3 wires on the compressor and check each pin to copper and see if you have a short. I would look for burnt wires. I would make sure I had continuity between all 3 pins. I would check them wires that are connected to the contactor. You say it is pulling down (the fan comes on) so power is getting to both the compressor and the fan IF them wires are all good at the contactor. Which they look suspect.

[michaeljc70]

Thanks for all the help.  I bought you a beer 

When I had time to look at it closer, the red wire was burnt and completely detached from the capacitor.  I reattached it and it is working great.

I need to get a new wire clip- the one in there the wire end was completely gone/burnt.  I hacked it for now with electrical tape since it is supposed to be 95 today.

[JWWebster]

Glad ye could Git her done!