Need a better understanding of how Air Conditioners work

[_RaT_]

Do you know how AC units work or have a good website full of the details? Specifically, my home AC unit is a split system. The compressor outside has the two copper lines running to it. One large and insulated, the other small and un-insulated. I always thought the big one got very cold at the compressor and the small one very hot. While my large line is cool, its never freezing. On the otherhand, the small one is lukewarm at best. Is this typical? Does the small line bring compressed liquid freon to the unit in the house? I think that is called the evaporator. Why would the large one be freezing cold if the air in the house is warm or hot, is it not taking enough cold away? I want to know more about AC, a real weak area for me. Thanks, Rat...

 

[barticus73]

I just had a problem with mine in that the large copper tube actually froze up. Come to find out the problem was that the air filter was too plugged and not allowing enough air flow to remove the 'cold' from the pipe so it froze. I left the unit off for a few hours, put in a new filter and it has worked great ever since.

 

[EarPlug]

Rat,

Try this web site http://home.howstuffworks.com/ac.htm

Jack

 

[frank_f15]

RAT: I will try to give you a basic explanation on how a/c works. refrigerant GAS is taken in to the compressor and compressed to a high temperature high pressure gas and then sent to the condenser which changes it to a high temp , high pressure liquid then sent to Evapator wher it goes to an expansion valve or capillary system which then changes it to a low pressure , low temp saturated gas which actually does the cooling, the heat taken from the room actully makes sure it is GAS before it goes back to the compressor and starts the cycle all over again. IT MUST BE GAS before entering the compressor. this is a very Basic explanation, but all A/C and /or refrigeration works off this basic principal. hope this helps somewhat

 

[kenmac]

Rat , when you say the suction line is cold. Are you measuring this temp with a thermometer or just by feel ? There could be several things wrong . Improper charge is one reason ,not moving enough air across the evap. coil is another , your compressor going bad is another .Ie; bad piston rings, bad valves. How about the duct work ? has it fallen apart some where ? If the unit is under charged or over charged it won't cool correctly, but the suction (large line ) could still feel cold. Hope this gives you a place to start looking.

 

[PineRidge]

The temperature of the suction line (larger one) And the liquid line (smaller one) will differ because of ambient temperatures at the condensing unit and the actual load on the evaporator coil. The correct way to charge is via a set of refrigeration gauges or a sight glass in the case of an expansion valve. For precise amounts of refrigerant like in an automobile system the charge is actually weighed in.

 

[kenmac]

I charge all my a/c units by super heat

 

[_RaT_]

Ken, the large line is cold (measured by my hand) but not freezing with frost on it as I sometimes see on other units. I guess it makes sense that this line should not be a solid white mass which would indicate that the evaporator is not absorbing as much heat as it should or perhaps not enough air is getting across it. (these are my assumptions anyway) I am not having problems as much as I want a better understanding. Sigarms has messaged me with some great advice. I appreciate all the comments, thanks, Rat..

PS whats "Superheat"

Rat , when you say the suction line is cold. Are you measuring this temp with a thermometer or just by feel ? There could be several things wrong . Improper charge is one reason ,not moving enough air across the evap. coil is another , your compressor going bad is another .Ie; bad piston rings, bad valves. How about the duct work ? has it fallen apart some where ? If the unit is under charged or over charged it won't cool correctly, but the suction (large line ) could still feel cold. Hope this gives you a place to start looking.

 

[kenmac]

Sigrams knows his a/c . Since you say you have very limited knowledge of a/c .The only way I know to explain superheat is, that it is a method of charging a unit so that you get max cooling/ efficiency from your unit.Others may know a better way of explaining this to you.If your unit is frosted (unless it's a heat pump in the winter) you have problems ie; low refrigerant ,etc; good luck in your quest to learn more about a/c.

 

[Sigarms]

Sigrams knows his a/c.

Thanks, but I beg to differ. Just know allot of men who are smarter than myself who will take the time to actually teach me something.