AC unit acting up


  #1  
Old 08-31-10, 06:31 PM
B
Member
Thread Starter
Join Date: Aug 2010
Location: USA
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
AC unit acting up

So I have searched and searched the internet for months now, had 2 separate repair man come out, one of which actually knew what he was doing. Anyway... here is the story...

We already know the 2.5 ton is too small for our 2670sf home, however, when it works, it keeps the house at 76-78 which is perfect for us.

First the unit started short cycling, about every 15 seconds. I went up, played with the safety switch on the door of the furnace, and it seemed to fix it. Not sure why but maybe the door wasn't quite tight enough to hold the switch down (See pic 3). Started doing it again a couple days later, went up door was on tight, so I decided to tape down the safety switch in the on position (I know it defeats the purpose) It seemed to start working again for a day. Started acting up, so I went up in the attic and sweat it out for about an hour, watching the unit cycle. I observed a filter like pad (see pic 2) below the main fan and control board kept getting sucked up around the control board when the fan was on and the door was closed. The felt pad is screwed in, so I figured it had a purpose, even though it is not filtering anything. But after the unit would run for a bit, I figured maybe this pad is causing the electronics to get hot, and shut off? So I put a heavy weight on it to keep it from flying up, again AC unit appeared to be fixed for a few days.

Started up again today and now I am frustrated. The entire unit turns on. Runs for about a minute, and then the outside condenser/fan began acting up. The furnace blower is working properly, at least I mean it is staying on, so I know it's not the safety switch or that pad. It continues to blow even with the outside condenser and fan off. But here is what the outside is doing now.

Turns on normal for about a minute, hear a pop in the arrowed area (See pic 1) and condenser shuts off, fan stays on. 10-15 seconds later, condenser turns back on, 10-15 seconds later, shuts off and fan stays on. Condenser turns back on at random then off/on/off quicker and quicker, each time that arrowed areas pops. Finally after 3-4 cycles, fan and condenser shut off for about 20-30 minutes, and start the cycle all over again.

As soon as the condenser turns on, the line gets nice and cold instantly, so I imagine plenty of free on. To me, either something is getting too hot (Electronic) or maybe getting too cold, but I don't see frost on any lines, so I just don't know.

It seems like I am just chasing one problem to be fixed only to find something else quits working once it is fixed...

Please help.





 

Last edited by BobbaBuey; 08-31-10 at 06:47 PM.
  #2  
Old 08-31-10, 07:09 PM
G
Member
Join Date: Oct 2002
Location: Hamilton County, Ohio
Posts: 3,927
Upvotes: 0
Received 2 Upvotes on 2 Posts
Let's start with the outside unit. It appears that your arrow is pointing to the contactor. This is basically a 220 volt switch operated by a relay or soloniod, which powers the outside unit. Normally the thermostat, when it calls for cold, signals the contactor to close. It does slam on or off with a noise.

The contactor may also cycle on and off if it gets a signal that there is low freon. It does this to protect the compressor. Have the system pressure checked.

What is under the foam pad? Is it the cold air return, the floor, or what. I can see part of the furnace blower. It must pull air from the cold air return to send it through the A/C coil and on to your living area. If the foam is a home made filter, scrap it and replace it with a real, properly sized filter.
 
  #3  
Old 08-31-10, 08:31 PM
B
Member
Thread Starter
Join Date: Aug 2010
Location: USA
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
The system was filled with free on by one of the repairman that came out then checked again about 6 months later, and he said it was holding the free on in just fine.

There is nothing underneath the filter like pad, hence why i am not sure what to call it since it is not filtering. it is just resting on the metal casing that houses the fan. the air gets sucked from the big open tube on the left, goes up the fan, then into the cooling part of the unit. I pulled the pad out most of the way to realize it was screwed in on the edges, so I just left it, but made sure it stopped getting sucked up by the electronics. Here is another shot of the pad. I don't know why it is there, because there is nothing underneath it.

 
  #4  
Old 09-01-10, 06:03 AM
C
Member
Join Date: Aug 2008
Location: Texas, California
Posts: 1,426
Upvotes: 0
Received 8 Upvotes on 8 Posts
The pad is for insulation purpose only. What you need to find out is why the contactor pops out all the time. Use an insulated screw driver push the button in and see if that starts your system. (That button in -power on, the button out- power off)
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: