How come my central air evaporative is full of ice- Little air could pass through

 I have a two story house with 2 AC system. Large one for down stair,
and small one for upstair.

For some reason, I noticed the rooms upstair became very hot. I
checked the vent and there was little air flow coming out. I went up
the artic and open up the blower box. The fan was operating, but the
evaporative had become a big block of ice so no air could pass
through.

I turned off the unit to let the ice melt away, and spend the night on
the couch. Next day, I turned the unit on, the air flow through
normal. But 2-3 days later, I felt the problem is coming back again
with little air flow out of the vent.

It's July in AZ. Little humid but not like Texas.

Wonder if the system would have any de-icing cycle, and the de-icing
function may not be working properly.

Appreciate your expert opinion. Thanks.

  On Thu, 24 Jul 2003 14:25:09 GMT, Chris Hill


What Chris said.

 On 24 Jul 2003 20:39:00 -0700, dtmstran@hotmail.com (DTT) wrote:


I don't know why it is that way, but it is.  I wouldn't replace a
10-year-old unit if this is its first breakdown.

 It can, but I'll let someone else explain why.
I would change the filter first, if you haven't done so recently.  If
the problem reoccurs, have the refrigerant topped off.

dtmstran@hotmail.com (DTT) wrote in message

 I thought about that physics too but then I asked myselve why it does
not always true in a car AC.

Last night I turned off the AC but left the fan running all nite. This
AM, there is still little air blow out of the vent. You would think
all the ice must have melted already.

Somethimg else going on here. Maybe the heat-exchanger is clogged up
with crap. How could it happed? I only used 3M filters and changed
every 6 months or less.

Check back in for what I find out.


bob@hobbes.dtcc.edu (Bob Rahe) wrote in message