Evaporator coil freezing up


  #1  
Old 05-29-02, 11:46 PM
wyres
Visiting Guest
Posts: n/a
Evaporator coil freezing up

My evaporator is freezing up. So is the return line going into the compressor unit outside.

The same thing happened last spring. At that time, we called a service man who said that an extra air filter my girlfriend had added was restricting the airflow over the coil, and without adequate air flowing over it, it got too cold and froze. As per his instructions, we removed the extra filter, allowed the unit to thaw, and it worked just fine.

This year, I cleaned the filter, (electrostatic with a metal mesh pre-filter, no extra filter installed this time) checked all the vents for obstuctions, and made sure they were open. There seems to be good airflow coming from the air registers. However, the evaporator keeps freezing up.

One other difference this year, the portion of the return air duct that was in the attic was completly uninsulated. I insulated it. This should make the air coming to the coil a bit cooler.

Anyone have any thoughts?
 
  #2  
Old 05-30-02, 12:01 AM
kaybyrd's Avatar
Member
Join Date: Feb 2002
Location: N.W. MS.
Posts: 1,771
Received 0 Votes on 0 Posts
May be low on freon. Most local guys will check it for free/low service charge.

Thought mine was too, but no air flow out vents after awhile. Freon fine, coils blocked causing freezing and rstricting the air flow.

Kay
 
  #3  
Old 05-31-02, 12:55 PM
wyres
Visiting Guest
Posts: n/a
The evaporator coils appear clean, I can shine a flashlight through them, doesn't look like too much dust.

Freezing seems to be a common problem, does anyone know what the usual causes are?
 
  #4  
Old 05-31-02, 01:20 PM
jonathanisaac's Avatar
Member
Join Date: Feb 2002
Location: Earth
Posts: 224
Received 0 Votes on 0 Posts
The common causes for a coil freezing are:

1. Dirty filter

2. Plugged up cooling coil

3. Blower speed too low

4. plugged up blower

5. Low Regrigerant charge
 
  #5  
Old 05-31-02, 01:38 PM
kaybyrd's Avatar
Member
Join Date: Feb 2002
Location: N.W. MS.
Posts: 1,771
Received 0 Votes on 0 Posts
According to the service men that just came to fix my a/c, it was low on refrigerant. It is working fine now. I am concerned as to why the first guy said the refrigerant was okay, but the company that came out put their gauges on there and said that it was low and the valve was leaking. Ended up needing over 1 1/2 pounds of freon.

So much for trying to help out the small business' in this area, I think I will stick with a reputable company from now on. I should have known since he diagnosed it as having the coils blocked without even being able to access them. Live and learn on this end.

I hope this helps someone else, as well.

Kay
 
  #6  
Old 05-31-02, 05:10 PM
jonathanisaac's Avatar
Member
Join Date: Feb 2002
Location: Earth
Posts: 224
Received 0 Votes on 0 Posts
So was the leak fixed, or did the tech just pump more gas into the unit.
 
  #7  
Old 05-31-02, 06:34 PM
kaybyrd's Avatar
Member
Join Date: Feb 2002
Location: N.W. MS.
Posts: 1,771
Received 0 Votes on 0 Posts
He actually had to drain the freon and then remove and replace the valve outside. Then he filled it back up. I don't know how much he removed to begin with, but when he replaced it he said that he had to add 1 1/2 pounds. My son was here when he came, I asked Lee the same questions to make sure that it was done correctly.

Kay
 
 

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