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Ask Airheatman Your Own Question
Airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 7509
Experience:  Furnace, A/C and heat pump specialist.
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I have a Carrier 38HDC air conditioner. The air conditioner

Customer Question

I have a Carrier 38HDC air conditioner. The air conditioner is not working.
When I came home from work, I noticed that the thermostat was set a the usual 73 degrees, but the indoor temp was 80 on the display. No cool air was coming from the vents, but the light indicating that the unit was red, not green. Indicator as to whether the unit is activated or in in a holding pattern. Red is holding, green is activated.
I went outside to check on the unit, I noticed the following:
The fan motor was still going and the pipe that leads under the house has "frozen." I believe this line was the "vapor line." I turned off the unit to see if it would "cool off" and turned it on again this morning.
Upon turning on the AC the "thawed pipe" started to frost over and no cool air came from the vents. When I turned the unit off again and tried to initiate the fans only, those did not go on.
The unit has been here more than 9 years, but other than that, I cannot say.
Submitted: 2 months ago.
Category: HVAC
Expert:  Airheatman replied 2 months ago.

Sounds like the issue is with the indoor fan not coming on causing the unit to ice.

1.Can you give me indoor model number

2.Do you have a meter for testing voltage

3.Can you do some hands on troubleshooting?

Customer: replied 2 months ago.
Indoor model number?
No meter and very, very limited troubleshooting.
I am more interested in the type of questions and range of "services" I would be looking to discuss with a repairman. For example, I want to know if that sounds like a condenser issue. a leak issue or other. Chances are some "highly rated" repair service company tech is going to show up and try to sell me the latest bulk purchased new air conditioner after I spend $300-600 on his services trying to fix this one. I just want to have an idea of the kinds of issues tat this could be.
Expert:  Airheatman replied 2 months ago.

I understand.Let me make sure I understood correctly.The lines were iced yesterday.This morning when you turned on the indoor fan that blows air did not come on correct?

Customer: replied 2 months ago.
Correct. It had over 12 hours to thaw.
Expert:  Airheatman replied 2 months ago.

Ok, when the outdoor unit comes on ,the indoor fan that blows air across the inside(evaporator) coil has to come on simultaneously.If it does not, the indoor coil starts to ice and will ice the copper lines all the way back and including the compressor.

Most likely issue is going to be that the indoor motor has failed or the control board that tells the motor to come on is failing to do so.

Expert:  Airheatman replied 2 months ago.

The following are reasons unit would ice.

1.Slightly low on refrigerant

2.Restricionin the refrigerant circuit (kink, metering device, filer drier)

3.Low or no air flow across indoor coil.

Since unit was cooling fine until yesterday I do not suspect low on refrigerant or a restriction.The fact that fan on inside does not come on narrows it down to either the fan being defective or the control board not telling it to come on.

Either of those two should cost around 300 to 400 if unit is out of warranty.

If you have further questions, please let me know.

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