What the Heck?


  #1  
Old 09-15-09, 11:42 AM
L
Member
Thread Starter
Join Date: Sep 2009
Location: South Carolina
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
What the Heck?

Just had a new Goodman outside unit installed two or three weeks ago. It seems to be running fine.

In the center of the attic is a Carrier air handler, model FA4BNF030 (008AAAA) that is about eight years old. The fan in the unit is 1/4 hp. A few mornings ago my wife noticed that ice cold air was coming out of the air intake in the hallway. My german shepherd loved it - me...not so much. No air was coming from the vents. The fan would not run in 'Cool' but would run when switched to 'heat.' I don't think the cool air was actually blowing out of the intake so much as simply settling to the lowest point, as cold air does.

I contacted a fella I work with who knows a bit about A/C's and he said it sounded like the capacitor on the air handler was bad. I bought a new 7.5 uf yesterday and installed it. Turned the unit on and it worked fine - for about six to eight hours. We noticed the same problem mentioned above when we returned home at 10pm. I turned the unit off and again called the fella above. He seems stumped.

I came home this afternoon at 1:25 and turned the unit on and, surprise, it appears to be working normally over an hour later. I'm watching it to see just how long it lasts - I have a small piece of paper stuck to the intake.

I trouble shoot crime scenes, dead bodies and the occasional computer - so I'm going to try going the cheapest route first.

The capacitor was less than two bucks. Next in the chain (I'm assuming" would be the relay?? My A/C friend says he's never run across this weirdness before, but all things mechanical conspire against me.

Any advice on how to proceed would be most welcome and sincerely appreciated.
 
  #2  
Old 09-15-09, 12:15 PM
dun11's Avatar
Member
Join Date: Feb 2009
Location: Local
Posts: 753
Upvotes: 0
Received 1 Upvote on 1 Post
Could be a bad high speed winding in the blower mtr, motor heats up and trips on thermal, motor cools down and runs, motor runs in heat because its using low speed.

Would need a meter and the knowledge to use it to go any further.

Just for the heck of it, check the refrigerant lines at the airhandler for ice next tiome it happens
 
  #3  
Old 09-15-09, 05:02 PM
L
Member
Thread Starter
Join Date: Sep 2009
Location: South Carolina
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
It is now about nine hours since I fired the unit back up. The temp is a comfortable 74 degree. And the unit is currently not blowing. I kicked the thermostat down to 60 and it kicked on and seemed to be sucking just fine.

Any ideas on why this problem occurred or why it seems to be so hit and miss?

Thanks
 
  #4  
Old 09-15-09, 05:06 PM
L
Member
Thread Starter
Join Date: Sep 2009
Location: South Carolina
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Originally Posted by dun11
Could be a bad high speed winding in the blower mtr, motor heats up and trips on thermal, motor cools down and runs, motor runs in heat because its using low speed.

Would need a meter and the knowledge to use it to go any further.

Just for the heck of it, check the refrigerant lines at the airhandler for ice next tiome it happens

Thanks. Both times it has done it we checked for ice - there was none. Let me rephrase that - there no ice at the outside unit either time. There was no ice around the air handler the second time. My wife did say she checked outside the other morning when it first was noticed. She didn't see any ice, but the ground around the drain was like a swamp.
 
  #5  
Old 09-19-09, 09:42 PM
V
Member
Join Date: Sep 2009
Location: Alaska
Posts: 22
Upvotes: 0
Received 0 Upvotes on 0 Posts
Originally Posted by LCCrime
Thanks. Both times it has done it we checked for ice - there was none. Let me rephrase that - there no ice at the outside unit either time. There was no ice around the air handler the second time. My wife did say she checked outside the other morning when it first was noticed. She didn't see any ice, but the ground around the drain was like a swamp.
Great analysis by DUN11 !!!!

But.... you MUST check for the ICE on the INSIDE unit which may be in your attic.
Wherever it is you need to find it and investigate for ice on those lines at the INSIDE unit.

What DUN11 is thinking is the INSIDE unit FAN is failing to work at times and the prescence of this ice AT THE TIME will be a good indication to verify his hypothesis.

But like a good crime scene, you have to catch it in the act.
Later and the ice will melt and the clues will be gone so you have to investigate at the time of failure.

The inside unit (air handler) blower motor 'may' be starting to have intermittent problems. Such is the nature os all beast.
They don't HAVE to be nice and just FAIL. They often try to be as sneaky as possible to confound our best troubleshooting methods and practices!!!

+++ to DUN11
 
  #6  
Old 09-20-09, 12:16 PM
Skip4661's Avatar
Member
Join Date: Dec 2008
Location: West Michigan
Posts: 255
Upvotes: 0
Received 0 Upvotes on 0 Posts
You should check the low voltage wiring connections, at the thermostat and air handler, especially the G terminal. But from my experience I have seen more bad relays than loose wires. The relay may or may not be located on a circuit board, you would need to verify this with the schematic.
 
  #7  
Old 09-20-09, 08:37 PM
L
Member
Thread Starter
Join Date: Sep 2009
Location: South Carolina
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Well, as of tonight there have been no further problems. I would tend to agree with the 'intermittent' hypothesis and expect to lose the relay or the fan sooner rather than later. I appreciate the fact that you folks took the time to reply and you have my sincere thanks.
 
 

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