Central Air Unit Not Cooling House

[BrendanMowgli]

I have 2 units- one upstairs and one downstairs-

The upstairs is blowing- I feel the air blowing- the thingamabob outside (can't think of the name) is operating, but no cold air. I did notice that there's no water being pumped out.

I hear its the compressor, but hopefully it's something else. Is there a few other checks I can do before I call the rapis- I mean the HVAC guy?

Thanks!

[cabinetman]

If the compressor (outside), isn't running, it could be as simple as a start or run capacitor.
.

[LCHIEN]

the thingamabob outside is the compressor unit, it actually has three major parts a relay, cooling fan and a compressor. You may hear and feel the fan running but the compressor needs to run to cool. If the air blowing out the fan, is it warm? if its just outside temp and not significantly warmer than the outside air then the compressor is doing no work. THis could be because the compressor is not running or there's no freon to compress. If the compressor fan is running you also have power to the compressor unit. and the thermostat (in the house) and relay are working.

When you have air circulating from the vents in the house, the circulation fan (usually connected to the ductwork in the attic), this tells you the thrmostat is working and has tried to command the circulating fan and the compressor unit to run.

So your problems may be this:
1. Low freon due to leak - could be in plumbing, connection or compressor - could be cheap or very expensive depending upon where the leak is and what needs to be fixed or replaced to stop the leak.
2. Compressor shot - very expensive.
3. compressor start capacitor failure - may be fixable.

Good luck. its hot down here.

[eezlock]

central air not cooling house

I don't think that anyone else said it....check to see if the breakers or fuses at the condensing unit (outdoor unit) have not been blown by an overload
or short circuit. The condensing unit does not "pump out" any water, any water you see outside from a running unit is condensation that comes from the indoor coil unit and is draining outside. I would first check a few areas
for trouble before calling the HVAC guys, might save you some money.

[LCHIEN]

He did say that "the outside thingamabob was operating" - if the compressor unit or condenser (outdoor) is blowing air with its fan then the breaker that supplies it is not tripped or bad... although the compressor itself may be dead. If that fan is not running then there is a chance that the circuit breaker is tripped - which may or may not indicate that there's an electrical problem - you can try reseeting the CB in this case and see if that fixes it for good (random trip) or if it trips immediately or within a short time (day or so) then you have an electrical overload (compressor going bad) or a bad breaker (easy to replace).

[tommyt654]

Check your filters. If they are dirty or clogged this will cause the unit to freeze up and run warm thus no cold air.Also make sure your drip pan is unclogged and allowing the condensation from the unit to flow out. I,ve had many a units drip line clog before resulting in a wet spot on the ceiling eventually.

[pelligrini]

Was this a sudden stop in cooling, or a progressive degradation?

Progressive would lead me to believe it is a coolant leak. That can also be coupled with freezing as tommy suggests. I think the coils can ice over if there is too much or too little coolant.

[cabinetman]

Was this a sudden stop in cooling, or a progressive degradation?

Progressive would lead me to believe it is a coolant leak. That can also be coupled with freezing as tommy suggests. I think the coils can ice over if there is too much or too little coolant.

The coils can also freeze over from a dirty or blocked filter not allowing enough air flow. A cure for that is just to run the fan on "on" and not cool, or just leave on "off". Change the filter, and when the ice melts, you're good to go.
.

[pelligrini]

Change the filter, and when the ice melts, you're good to go.

Except when there is enough ice to block the drains. In a recent condo job the builder replaced the wood floor around the AC unit for a second time due to the ice melting with plugged drains. It was a clogged filter that brought on the ice.

The first time was the painters breaking a sprinkler head on the 3rd floor of the unit. Just one head can certainly flow a lot of water down through a unit.

[billwmeyer]

dirt!

The last time this happened to me, the coils on the condenser unit were dirty. The service man just borrowed my garden hose, opened up the unit, and cleaned the unit. If you try this, make sure you kill the power. Better safe than sorry.

Bill

[Daryl]

Mine was broke down recently, it turned out to be the condenser fan was shot. It would run sometimes and other times not.

[LCHIEN]

Mine was broke down recently, it turned out to be the condenser fan was shot. It would run sometimes and other times not.

you're lucky, that's about the cheapest thing that can break short of the thermostat or the breaker.

[Daryl]

you're lucky, that's about the cheapest thing that can break short of the thermostat or the breaker.

Yep, I was about ready to buy a new one, this one is 15 years old and three years ago we had a connection break and lost the freon, maybe one more year.

[unclecritic]

If the fan is running on the outdoor unit, be sure the compressor is also. If its not (kinda sounds like a small air compressor) check to see if the disconnect (gray box on the side of the house) is of the fused style. The fans in most condensors only run on one leg of the 220 volt, so you may only be getting 110 volt to the unit if one of the fuses are bad. If you check the fuses and find one that is bad, replace it with the same size and make sure you get time delay fuses.

Spray the aluminum fins of the outdoor unit with simple green or a similar cleaner and let it set for about 10 minutes and hose it down working from the bottom up and then back down. Dont use a full force spray or you will damage the fins.

The indoor coil is a little different if you can even get to it easily, as most installs have them almost impossible to look at let alone slide out and clean without reclaming the freon and cutting the lines. there should be a panel which will compromise most of the front of the coil that is held on by screws. pull it off and peak inside. if you can clean it, dont use any cleaner on an indoor coil otherwise your whole huse will smell of whatever cleaner you use for a long time. Just get it wet and and use a soft bristle brush to get any hair and dust built up off of it, again being careful not to bend any fins over. If its anymore involved than this to get it clean, then you should probably call a rapi.. uh.. i mean.. HVAC tech.

And please change your filter. I hate the look on peoples faces when I tell them i have to charge them $125 to change a $2 filter.

If this still doesnt solve your problems then you probably have an issue on the freon side of things... compressor, low to no charge, low pressure cutoff, run/start capacitor for the compressor... But doing the stuff i mentioned above will rule out alot of stuff for the tech and save you money... and anyone that does this oncve a year will get noted efficiency out of their A.C. systems.

at least you didnt call the hvac guy a thief lol

[Greg in Maryland]

I hear its the compressor, but hopefully it's something else.

My vast professional experience with A/C units leads me to conclude that the dohicky, which is connected to the thingamabob via the hickydoodle is completely shot.

At times like this, you have to do what ever you can to get it fixed. I would think that a new router and a omni jig would do the trick. Perhaps if the situation is completely hopeless a new 18 inch bandsaw would be called for.

Good luck and welcome to the forum.

Greg