Hi,

I have a strange problem with the home air conditioner. Everyday afternoon,
it turns on but does not have the blower fan on. The compressor and the
outside unit fans turn on. The vents have no cool air coming out of them
and so the house gets warm.

I have to come home and turn the thermostat from 'cool' to 'off', leave it
for about 5-10 mins and turn it back to 'cool'. Then the AC kicks in and
the blower fan turns on. Cool air comes out of the vents and the rooms
start cooling down slowly.

I checked the thermostat and the fan is set to 'Auto' and not 'On'. Even
when I turn the switch to 'Fan On' position the blower fan does not seem to
start unless I do as above.

The unit is a 8 year old Carrier.

Any ideas on what could be the problem?

TIA

R. Kannan wrote:
Any ideas on what could be the problem?

Most likely cause is a bad start capacitor (if the blower motor has
one), otherwise it may be new blower motor time.

I had a guy look at it. He says the there is low freon in the system and so
the heat exchange are is 'icing up' and not allowing bair blown by the
blower fan to get through. I would imagine that if the freon level is low,
it will not cool down at all. Why would it 'ice up'?

Any truth to what he says?

Travis Jordan wrote:

R. Kannan wrote:
Any ideas on what could be the problem?

Most likely cause is a bad start capacitor (if the blower motor has
one), otherwise it may be new blower motor time.

R. Kannan wrote:
I had a guy look at it. He says the there is low freon in the system
and so the heat exchange are is 'icing up' and not allowing bair
blown by the blower fan to get through. I would imagine that if the
freon level is low, it will not cool down at all. Why would it 'ice
up'?

Please don't top post.

When the refrigerant charge is low the evaporator coil is starved for
refrigerant. This results in reduced pressure at the inlet piston or
expansion valve, thus allowing the refrigerant to vaporize at a lower
temperature - below 32 degrees. At this point the first part of the
coil will freeze. Then, since ice is a fairly good insulator the
refrigerant will now travel further through the coil before encountering
an exposed surface. More ice forms and the process continues. Gradually
most or all of the evaporator coil will be covered with ice. This of
course blocks air flow through the coil.

Travis Jordan wrote:

R. Kannan wrote:
I had a guy look at it. He says the there is low freon in the system
and so the heat exchange are is 'icing up' and not allowing bair
blown by the blower fan to get through. I would imagine that if the
freon level is low, it will not cool down at all. Why would it 'ice
up'?

Please don't top post.

When the refrigerant charge is low the evaporator coil is starved for
refrigerant. This results in reduced pressure at the inlet piston or
expansion valve, thus allowing the refrigerant to vaporize at a lower
temperature - below 32 degrees. At this point the first part of the
coil will freeze. Then, since ice is a fairly good insulator the
refrigerant will now travel further through the coil before encountering
an exposed surface. More ice forms and the process continues. Gradually
most or all of the evaporator coil will be covered with ice. This of
course blocks air flow through the coil.

Thanks for the explanation. I guess the reparman was right.