Help with A/C


Hey all!

I can hear my outside unit come on but there is no air coming through the vents. I can hear a slight humming noise though. (Fan issue?) The interesting part is that when I turn the heater on, warm air blows through the vent and when I switch it back to cool, then cool air comes through. It's a temporary fix but it's a pain to turn the heater on first just to get the fan running and then switch it to cool. Please help!

  12 answers
  • Vimarhonor Vimarhonor on Aug 22, 2020

    Hello. Could your coil be freezing up. Might be worth checking.

    We have had that happen

    This link might be helpful.

  • I agree , it could be the coil, but I'm a fan of calling in a professional to check it out.

  • Mogie Mogie on Aug 22, 2020

    There are some things that I pay to have done and this would be one of them. How old is the unit you are referring to?

    Have you called the company that made it and asked them?

  • Cynthia H Cynthia H on Aug 22, 2020

    I agree about calling in an HVAC professional. We have the same time of central air and heat and it is too involved for most DIYers. Hopefully, it's a simple repair, like a faulty switch. Good luck and stay safe!

  • Flipturn Flipturn on Aug 22, 2020

    Is your A/C unit installed in a window? or is it integrated with your HVAC/furnace and thermostat? If it is not the latter, no need to call an HVAV repair person.

    If it is a window unit, yes, unfortunately the coils do freeze up now and again, especially if you have had the unit turned on for extended periods, and/or on High setting.

    The 'fix' is to shut the entire unit off for as much time as it takes for the coils to thaw.

    When you have been turning the unit on Heat, the fan is blowing the hot air on to the frozen coils, and thawing them. By simply turning the entire unit Off, the coils will thaw out on their own, without having the room become extra hot due to the blowing hot air.

  • William William on Aug 22, 2020

    Sounds like it's a fan motor problem. Most fan motors are three to four speed. Low and medium low usually for heat. Medium high and high for cooling. Since you hear a slight humming noise the med-high or high speed windings are more likely shorted. When you put the heat on first and switch to cool the lower motor speed stays on. Get an HVAC tech. The fan motor may need to be replaced. he can check the operation with it out of the unit.

  • sounds like a setting issue. Check the manual and make sure you are using the correct settings.

  • Kathy Gunter Law Kathy Gunter Law on Aug 23, 2020

    It sounds like it might be low of Freon. Check to see if there is any signs of icing over.

  • K. Rupp K. Rupp on Aug 23, 2020

    I am assuming this is a heat pump. Could be fan motor and/or the reversing valve, or the mechanism that actuates it ie: the coil could have a problem.. ugh....heat pumps always have so many issues with switching back and forth with different seasons. I don't think it's good for the unit to switch that quickly from heat to AC. I thought you were supposed to wait a while before doing that. What a pain! Yeah, unfortunately I would call a technician to really narrow it down.

  • Ken Erickson Ken Erickson on Aug 23, 2020

    Call your local HVAC contractor. They can diagnose and fix your problem (correctly). We have our HVAC checked twice a year to ensure it works well.

  • Jocelyn Jocelyn on Aug 25, 2020

    Soooo...I called the professionals as many of you suggested. It was a faulty wire leading into the relay for the blower motor. $50 and 1 hour later and we're back to business as usual.

    Thanks for all of the help!

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