One of the most frustrating problems with a window air conditioner is if it starts
to ice up. For the owner of the air conditioner is can be perplexing.
When this problem occurs most people immediately think it is
the fault of the refrigerant gas. More often the cause is the result of other
difficulties.
It is most often the result of poor airflow.
Any time the airflow through an air conditioner is
restricted the cooling system becomes affected. If taken to extremes the
critical pressure-temperature balance of the cooling coil can be changed. If
they drop too low the cooling coils surface temperature can drop below the dew
point temperature of the room. When this happens the cooling coil will begin to
operate as a refrigerator rather than an air conditioner. Rather than simply
cooling the air it will collect and hold moisture. The moisture will freeze
onto the cooling coil where it will appear as ice.
The primary job of an air conditioner is to de-humidify, not
refrigerate, the room air. By removing the moisture from the room air it gives
us a feeling of comfort. To do this though the temperature of the cooling coil
must always be higher than the room's dew point. If it is allowed to drop below
the dew point the air conditioner will start to produce ice.Read this post.
With this information in mind the following are a few
problems that can result in your air conditioner icing up:
1. Dirty filter.
To avoid this replace or clean your filter every couple of
weeks of the cooling season. If a smoker do it every week. To clean filter
remove from air conditioner, wet thoroughly, and lay in bottom of a sink.
Sprinkle detergent (laundry detergent works well) onto filter surface. Allow to
sit for a few minutes. Add warm water to sink so that filter is completely
covered. Soak for 15 minutes. Remove from water and rinse. Allow to air dry.
2. Dirty or blocked cooling coil.
An air conditioner requires regular maintenance. Usually
every two or three years. Every year would be best, but this can be costly
unless you do it yourself. During cleaning the cooling coil should be degreased
and washed to remove accumulated dirt and debris. Degreasing is important to
remove any coatings on the coil. If not done greasy residue can trap and hold
air borne particles. They will build up on the coil and affect heat transfer.
If left too long this can result in the cooling coil becoming partially
blocked. This will produce a lower airflow.
3. Dirty or blocked condenser coil.
The condenser coil is the one at the rear of the air
conditioner. Its job is to dissipate the heat that is being removed from the
room. Just like the cooling coil it too must be cleaned every few years. Since
the condenser is on the outside of the home it becomes exposed to a lot of
dirt, pollen, and smog. Since airflow direction is from inside to outside it is
the inside surface of the condenser that becomes dirty. Therefore to clean this
part the air conditioner must be completely disassembled. If not cleaned
regularly an airflow blockage here can even burn out the compressor. Before
this happens though the lowering of airflow will affect the overall operation.
This can result in the compressor efficiency dropping, the internal
pressure-temperature relationships being affected, and the resultant production
of ice on the cooling coil.
4. Inefficient compressor.
As describe above an inefficient compressor can cause icing
up. If the compressor is not able to pump the refrigerant properly the cooing
coil may not get cold enough to shut off the cold control. It can hover just
above the cut off point. When this happens the cooling coil will begin to
refrigerate. Ice on the cooling coil will result. If the compressor itself is
at fault the air conditioner will have to be replaced. But note that many icing
problems are misdiagnosed as bad compressors when they were actually one of the
other faults discussed in this article.
5. Not enough refrigerant. Too much refrigerant.
Both scenarios can result in and icing condition. If your
air conditioner was repaired recently suspect too much refrigerant. Mixed with
an airflow problem this can be difficult to diagnose. If not repaired recently
then suspect airflow problems before considering a refrigerant imbalance.
6. Outdoor temperature too low.
Icing can occur if the outside temperature falls below 60
Degrees Fahrenheit. If the outside temperature is too low the air conditioner
pressure-temperatures can be affected. When the outside temperature falls the
cooling coil temperature will also fall. So much that the coil will refrigerate
the room air. This will result in the cooling coil beginning to produce ice.
This problem is more prevalent in the fall. If it is hot during the day but cold
at night suspect this problem as the cause of icing up. If this problem is
suspected try running the air conditioner in the fan only position. Leave the
re-circulating vent open. This will circulate the room air without cooling it,
while bringing in a small amount of outside air during the night.
7. Oversized air conditioner.
If the air
conditioner is too large for the room size icing up can result. If
oversized the air conditioner can short-cycle. This condition is usually seen
as the air conditioner starting and stopping every few minutes. Even though it
runs almost constantly the air conditioner will give poor cooling. Use a sizing
chart to determine what is the proper air conditioner size for that particular
room.
8. Cold control not shutting off. If the cold control does
not shut off the cooling coil surface temperature will drop below the room's
dew point and begin to refrigerate. This will allow ice to build up onto the
cooling coil.
9. Cold control bulb broken or loose. As in the previous paragraph
this will result in the cold control not shutting off and ice to build up on
the cooling coil. If this is suspected remove the front grille and inspect the
bulb. If broken replace cold control. If bent, kinked, or not securely fastened
suspect a problem here.
No comments:
Post a Comment