Central Air Problem

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67Dart440GT

67Dart440GT

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Anybody here good with central a/c units? I noticed today that it wouldn't turn on... so I changed the batteries in the thermostat and it turned on. Then I could tell it wasn't blowing very well and the line inside the house is covered in ice and water. The unit does run and it seems like I can hear freon moving in the lines. I can turn the fan on with the thermostat and hear it start and run but doesn't seem to blow very well but it does work and turn on and off.... any tips?
 
Try turning off the AC and switch it over to the 'FAN' setting. I believe your evaporator is iced up. The ice will melt with the fan only running. Give it some time and then try the AC again. Had this happen to a window unit.
 
The evaporator icing is a symptom of another problem, low refigerant or an air restriction on the return side (clogged filter?) are the first things to check.
 
I know squat about these, but I just had a new furnace installed and my a/c coil(???) is mounted on top of my furnace. Once they took the old furnace out, they cleaned the a/c coil with small brushes. I would imagine if its clogged, your lines will freeze up.
 
67Dart440GT said:
Is there usually a separate filter for the central air and heating?
Click to expand...

I dont think so, chk the furnace filter. If the coil has never been cleaned, I would say it would need cleaning as well. But that would be for a furnace guy...I have never done one.
 
Mine would ice up when it got low on refrigerant. I got by for a couple of years by recharging it in the spring but last year it wouldn't hold for over a few weeks so I replaced the unit this spring. It was a cheap brand that had worked well for about 13 years.
Dallas
 
I think I found the problem. When you run the fan it starts blowing just fine, then slows down and barely blows at all. I am assuming this is the motor inside the furnace.
 
Your condensing coil will ice up for a couple different reasons:

1. Low on freon or whatever they call the new stuff.

2. Cold air return filter is clogged/too dirty- I change mine at least once a month

3. Coils on the exterior of the compressor are clogged up with dirt/ leaves etc. Its a good idea to pressure wash or at least hose them out once in a while

4. Blower motor not running- if it runs fine with the fan switched to the ON position instead of AUTO on the thermostat- it should be fine. If so its probably one of the above

My unit has a very slow leak and I need to have it re charged a week ago and now it runs like champ. Before that it would freeze up a couple times a week!
 
Well after a ton of beating the old motor out of the squirrel cage I finally got it out... now I have to find the right motor to replace it with.. or just call the damn heating and cooling guy to finish it for me!
 
Look real close at your fan blades, They have a curve in them that builds up with dust and will not move as much air if they are built up with dust over the year's How old is this system ? and did you use a flash light to look at your cooling coils when you puled the fan out ? If the fan is going out and running hot go take it to a a/c supply company near you and they will fix you up with a new one " they will have a motor that is mad to fit many air handlers , like a universal motor". It will most likely need a new capacitor "motor start capacitor" talk to them and they will show you what wires go where, these fans have two to three speeds, Low for heat and so on.
I have worked on many central a/c units and they do need to be cleaned and serviced yearly to keep them running efficiently. It is well worth the money to have a person that knows how to clean the inside coils and I have seen them look like carpet over them :angry7:
If you have a 3 ton unit that need's the coils cleaned you are paying for 3 tunes and only getting 2.... Know. If your motor is bad remember to clean the squirrel cage fan blade before you reinstall it.. There will be an arrow pointing the direction the motor will turn and be sure to put the squirrel cage blades back the same way they cam out...
And just turning the power off on this unit will not keep you from getting shocked !! The the motor starter will hold a big shot of voltage like a battery , this is used to get the motor started These are called a capacitor.... if it has went bad it could have burned up your motor as it trays to start with out it... Talk to you local a/c heat and air parts suppler about this, I would hate to see you burn up a new motor with that bad start capacitor.
Dirty coils will make one freeze up and put a huge loud on you motor if ran this way. be very easy on the coils if they need to be cleaned, they have a brush that bends to help you reach and brush the heavy stuff off but after that they have a coil cleaner spray that will penetrate your coil and wash them out. Just be very carfull there is voltage in there with the power off. Keep us updated so I can jump back in here. when this is dune shut the power off at your outside condensing unit and wash the fine's off with a cleaner you can buy and then rinse it out softly so you don't bend the fins . I hope this helps and please be carfull
 
Thanks for all the info everyone. I decided to just have a company come and put an all new furnace in. The old one was made the same year as my wife was born! $2500 installed 90% with a 5 year parts and labor warranty. I just started college "again" working full time with infant TWINS. It feels good knowing we will be warm in a few months and cool for another few months. Thanks again for all the info!! This place is the best.
 
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