AC unit stops cooling but keeps running

I'm trying to get an idea of what is causing a problem with my AC unit. I'm in an apartment condo that has a central unit that heats and cools. The problem is that when the AC kicks in, the unit cools (the coils get condensation on them and get cool). After a while, the unit no longer cools anymore but you can still hear the condenser running. If you turn the unit off, wait a while and then turn it back on the same thing happens...it cools for a little while and then doesn't. It never satisfies the thermostat so it doesn't stop unless I turn the temp up and then you can hear the condenser stop.
The unit is about 10 - 15 years old, has been cleaned and has a new filter. Any idea whether I'm looking at a coolant leak, a condenser problem or something else here?
Thanks, Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Impossible to say for sure over the internet. But from what you describe, it sounds like it needs professional cleaning.
--

Christopher A. Young
You can\'t shout down a troll.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Find the schematic for your AC. It probably is with the owners manual or pasted to the cabnet somewhere. Use that to locate all control components (particularly thermostats) and verify they are switching at the right temperatures. Since its 15 years old, I assume it worked for most of that time and you are not looking at a bad design or insufficient power.
BTW Condensers don't run, they are just passive coils of pipe. Either the compressor or the fan(s) or both should run. A condenser might make a little noise from thermal expansion but that does not indicate running only a change in temp.
If you had a coolant leak, the cold coil wouldn't get cold at all or it wouldn't get cold enough. How much is enough I can't answer from here.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@hotmail.com wrote:

turning it off. When it cools, the protector resets.
Lubrication might help (although most are permanently lubricated nowadays), as might clearing anything blocking air flow around the compressor (e.g. debris and vegetation). I would also check that the voltage at the compressor is correct -- too low or too high can cause overheating. And you might also try replacing the run capacitor if it has one, especially given its age. Beyond that, it's probably a forklift job (i.e. replacement).
--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form snipped-for-privacy@prodigy.net.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Text inserted.
wrote:

turning it off. When it cools, the protector resets. CY: That sounds reasonable.
Lubrication might help (although most are permanently lubricated nowadays), CY: The compressors are typically lubricated with oil mixed in with the freon. However, the fan motor often has oil ports. Also, a dirty or dusty condnsor can cause compressor overheating.
as might clearing anything blocking air flow around the compressor (e.g. debris and vegetation). CY: Excellent. Or anything over the top of the unit, such as deck, awning, roof, etc.
I would also check that the voltage at the compressor is correct -- too low or too high can cause overheating. And you might also try replacing the run capacitor if it has one, especially given its age. Beyond that, it's probably a forklift job (i.e. replacement). CY: I can think of a few things that can be a problem -- and repairable. So, it's time to call a HVAC service company out. May very possibly be fixable.
--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form snipped-for-privacy@prodigy.net.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Condo? Water source on the condenser? Valve to that closed?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for the info everyone. First off, it was cleaned professionally so that one is out. And yes, I confused condensor with compresser...brain fart...the compresser continually runs but cooling drops over time.
As for the condo question, the valves are open (double checked that one, and it does cool initially ;) ).
With the age of it I'm thinking it might need replacing. Partially because it's a b***h to work on due to it's design (and the fact it's jammed in a space barely big enough for it, let alone my sweaty paws) and the contractors says that it'll be minimum $800 to fix it. $800 on a 15 year old unit doesn't seem like a wise move.
Thanks again for the advice.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.