Northern Virginia Real Estate and Community News Blog

HVAC Troubleshooting

System - Monday, May 18, 2020

I have great news for you!  No matter how long the winter, spring is sure to follow, and now each day one can sense Summer glowing happily and creeping on bare feet.  For all the joy that Summer heralds, in property management, we feel a sense of trepidation.  When will the first no AC call come in?  Most AC’s will start right up after their annual hiatus, but I am here to help the unlucky few that are met with the unlucky surprise of no cool, cool, air when the temperature goes up.  Below I put together a troubleshooting list to help get past the most common causes of no AC.  

  1. Check the thermostat.  The best way to troubleshoot is to work backwards from the user interface.  Is it in cool mode?  When first switching from heating to cooling, leave the unit off for a minute before switching modes.  It will prevent the occasional error between the thermostat and the air handler.  Is the temperature set below the room temp?  Each thermostat has its’ own tolerances.  The most common is about 3 degrees Fahrenheit.  If you set the temperature to 68 and it won’t go below 70, that may just be the tolerance of the thermostat.  Wait to call someone until you see a difference of more than 3 degrees.   Does it need new batteries?  Some thermostats are hardwired, but some are powered by batteries.  Just because the screen lights up doesn’t mean that the signal is getting to the air handler.  Replace the batteries and try setting the temperature again.  If that doesn’t work, move onto the next step.
  2. Does the System have power?  HVAC systems need electricity and refrigerant.   Next one would check the power going to the HVAC system.  First check the circuit breakers to make sure one isn’t tripped.  If you find a tripped circuit, flip it the opposite direction and then back to where it should be.  If it trips again, STOP, and call someone.  There may be a short somewhere and it needs a professional.  If the circuits all look fine, check to see if the emergency cut off, if there is one, isn’t switched off.  It will be near the inside air handler and look like a normal light switch.  It may need to be switched up or down. Try flipping the switch to see if the unit turns on.  These are often accidentally turned off because they are hard to distinguish from light switches.     
  3. Is the unit getting air flow?  So it seems like all systems should be go?  Next, check your filter or filters to see if the system doesn’t have restricted air flow.  HVAC systems are expensive and thus are designed to shut off rather than damage themselves if running improperly. Go ahead and put in a new air filter.  You had it on your to-do list anyways.  Next, touch the side of the unit to see if it isn’t frozen up.  A frozen unit might be a sign of low air flow or a refrigerant leak.  If the unit is frozen up, you will be able to see ice on it.  Turn the system off for a few hours and try again once the ice has melted.  If you start to see it ice up again, give someone a call.  It needs to be serviced.    
  4. Check your AC drain.  Still not enjoying the fruits or modern climate control technology?  Last thing you should check is the condensate line.  Many air handlers have a cutoff switch tied into the condensate drain.  If the drain is clogged, water can build up in the unit or drain pan and the AC will turn off to prevent water damage.  If you are in a condo, the system almost certainly has one.  You can try to gently clear the drain line or drain pan drain with a narrow-gauge item that is rigid.  The unit will start right up once the water goes down and the float switch opens.  That may get the AC working until a repair person can come out and do a more thorough line cleaning.   A technician will then be able to clear the line with compressed air and keep the AC blowing all Summer long.  

Here we are with the monster at the end of the story.  If all of that doesn’t get the AC working.  It is time to pick up the phone and call for service.  You fought the good fight and technology won.  It happens to us all.  Make the call and hopefully a few diagnostics and a part that they already have on the truck will get you back to enjoying the Summer heat safely inside a nice cool home.     

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