1. 2)Next, check the disconnect at the outdoor unit, called a condenser. To verify that a pull disconnect is supplying power to the condenser look for the “ON” lettering right-side-up at the top of the pull piece. If “OFF” is at the top and “ON” is upside-down, then power is disconnected.

    And, third, check the breaker in your electric panel to see if is tripped. A tripped breaker switch will be offset from the other breakers in the row and you will see a red box next to the switch in some panels to highlight that the breaker is tripped. If you reset the breaker and it immediately trips again, stop and call for service.
  2. 3)Your condenser could have a safety device that locks it off after sensing certain malfunctions. Reset it by shutting off the power at the breaker for the condenser in the electric panel. Wait about a minute, then turn the breaker back on. Because there is an built-in automatic time delay, it will take up to 10 minutes for the system to turn back on. If is shuts off again shortly after restarting, stop and call for service.

  3. 4)If there is a “RESET” button at the condenser, press it. If it shuts off again shortly after restarting, stop and call for service.

  4. 5)If there is a condensate drainage problem, then a safety float switch may have shut off the system. If you see a gadget like the one pictured below on the condensate water drain line near the air handler, pull the top and see if there is standing water in it.
    There is also another type switch that is clear plastic, to so you can easily see if there is any standing water in the condensate drain line, shown in the photo below.

    When your air handler is in an attic or other location where spilled condensate water would be a problem, then there will be a pan under the air handler, also with a float switch on the edge flange. If there is standing water in the pan, that means that your primary condensate drain piping is clogged and the drain from the catch is also clogged. Flushing out a condensate drain line is easy if there is a port built-in for it. If not, you may want to have an a/c service contractor do it for you.
    If you have a condensate pump (a small box with a pump on top, usually on the floor under the air handler), check to see if the holding tank is full. There is also a sensor here that would shut off the system. Since these are usually plugged into a 120V receptacle, also make sure it hasn’t come unplugged.
  5. 6)Check to see that the bottom front panel of the furnace/air handler is snugly in place. If you have recently removed the bottom panel of your furnace/air handler to change the air filter behind it, there is a safety switch along the top of the panel opening that shuts off the system when the panel has been removed or is loose. Make sure that panel is securely in place so that the switch is not activated. This only applies to systems where the bottom front panel of the air handler must be removed for a filter change or any other routine maintenance. The switch can be a lever-type, like the one shown below, or a pop-out button.

And if all these checkpoints turn up nothing, yes...stop and call for service.

While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
©2015 - McGarry and Madsen Inspection.


More blog posts about heating and air conditioning:

  1. How can I find out the size of my air conditioner?

  2. How can I find out the age of my air conditioner or furnace?

  3. The coils on my heat pump are covered with ice on cold mornings. What’s wrong with it?

  4. How much will I save on my utility bill if I get a new higher SEER air conditioner?

  5. What is the SEER of my old air conditioner?

  6. What is the difference between the “ON” and “AUTO” settings on my thermostat?

  7. Why are some rooms colder or warmer than others?

  8. The coolant line to the outside unit of my air conditioner is frozen. What's wrong?

  9. What is an HVAC system?

  10. Will a house without air conditioning pass a 4 point inspection?

  11. What does an ultraviolet air treatment system do?

  12. What size air conditioner is right for my mobile home?

  13. What does “AUX HEAT” and “EM HEAT” mean on my thermostat?

  14. What is the minimum SEER rating for a new air conditioner?

  15. What does the “AFUE” rating of a furnace mean?

  16. Why is there mold around the air conditioning ducts?

  17. What is a geothermal heat pump?

  18. How much life is left in that air conditioner?

  19. What is a “ton” of air conditioning?

  20. What does the MERV rating number on an air conditioner filter mean?

  21. What is wrong with an air conditioner when the air flow out of the vents is low?

  22. How much will it cost to replace my old air conditioning system?

  23. What is the difference between the SEER and EER rating of an air conditioner?

  24. Should I move the air conditioner into the attic?

  25. My air conditioner outside unit (condenser) won’t start and is making a humming noise. What’s wrong?

  26. What is an air conditioning heat recovery system?

  27. What is the best air conditioner for a mobile home?

  28. What is the average lifespan of an air conditioner?

  29. When should I switch the thermostat to “EMERGENCY HEAT” for my heat pump air conditioner?

  30. Why does the air conditioner condensate drain line need a trap in it?

  31. Should I remove an old whole house fan or keep it?

  32. Is it acceptable for an air conditioning condensate drain line to terminate under the house?

  33. What is the purpose of the vent grille over the bedroom door?

  34. Should I have a return air vent in the master bedroom?

  35. What is a jump duct?

  36. My air conditioner won’t turn on What’s wrong?

  37. Will closing doors reduce my heating and cooling costs?

  38. Why is there a wall switch next to the furnace or indoor unit of the air conditioner in the garage?

  39. Which one is better for a home heating system: electric or natural gas?

  40. Why does an air conditioner condenser need to be level?

  41. Why is it bad to have a clothes dryer vent near an air conditioning condenser (outdoor unit)?

  42. How can I tell if an air conditioner uses R-22 or R-410A refrigerant?

  43. Why is my air conditioner not cooling enough?

  44. What is a return air plenum for a furnace or air conditioning system?

  45. When is an auxiliary drain pan required under an air conditioner indoor unit (air handler)?

  46. Why does it take so long to cool a house when the air conditioner has been off for a while?

  47. What are the right words to use when talking about a heating and air conditioning system?

  48. What is a FanRecycler and AirCycler?

  49. Why is my bathroom vent fan not exhausting enough air?

  50. Why has the thermostat screen gone blank?

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