Air Conditioning Repair – 4 DIY Tips You Need Before Calling a Technician

Air Conditioning Repair – 4 DIY Tips You Need Before Calling a Technician

Help! It’s 90+ degrees outside, you are hosting a dinner party in a few hours…and your air conditioner (A/C) just quit! Therefore, the last thing you need, or want to be worrying about is air conditioning repair…am I right?

Sound familiar?

It seems like this exact scenario happens all the time, and it happened to me! Due to the fact that your air conditioner will always fail at the worst possible time, or on the hottest day of the year [Murphy’s Law], we’re going to give you a few simple DIY tips that will get you back up and running, and in no time at all!

Above all, this info may just prevent a delayed and EXPENSIVE service call from your friendly Heating, Ventilation, and A/C (HVAC) professional!

Lets get started!



First of all, your air conditioner only needs a few MAIN ingredients for normal operation. As a result, the rest is taken care of by all the other major A/C mechanical and electrical components that comprise your system.

Thermostat (user interface)

Electricity (main power from breaker panel and lockout switch)

Refrigerant (Freon)



Furthermore, it’s a given that the average Homeowner does not have the ability to repair major A/C system items or components. So, the focus and Scope of Work will be on DIY Homeowner repairs and tips.

Any additional repairs outside this scope may need to be performed by an HVAC professional / technician.



Also, before we can asses, inspect, or fix anything, we need to locate and identify some major items and A/C system components. The following should be located in your attic, basement, service closet, or garage, etc.

NOTE – Electrical Hazard: When working on ANY electrical equipment, ALWAYS make sure the main power source is unplugged / switched OFF / locked out BEFORE service or repair is attempted.

Air Conditioner Thermostat

  • Usually located on main level.
  • Sometimes on multi-levels.
  • Main control for the A/C unit.

Main Breaker Service Panel

  • Usually in the basement, service closet, garage.
  • Houses the two breakers that supply main power to the A/C System.

Air Conditioner Condenser

  • Usually located outside and close to the house.
  • Sometimes located on a roof.
  • Transfers heat; cools down and condenses refrigerant vapor into liquid.
Air Conditioner Repair - Condenser

Air Conditioner Repair – Condenser

Air Conditioner Condenser Service Lockout Switch

  • Usually outside near the A/C Condenser.
  • Locks out the power between the main breaker panel and the A/C Condenser.

A/C Air Handler (with drip pan)

  • Usually in the attic, and/or basement, service closet, garage.
  • A split-system may utilize an attic AND basement.
  • Usually located where the air filter is replaced (unless you have a cold air return filter box).
  • Filters, delivers, and returns the conditioned air – throughout the house and back to the unit.


A/C Air Handler Wet Switch

  • What is a Wet Switch? SEE THE VIDEO AT THE BOTTOM
  • Protects against flooding from clogged pan drain.
  • Usually located in the bottom of air handler drain pan. Looks like a hockey puck with a red/green light.
  • Should be located to the SIDE of the drain pan – out of the path of normal condensation drain/drips.
  • Location IS important!
  • Has a Test and Reset button.

AIR CONDITIONING REPAIR – 4 DIY Tips Before Calling a Technician

Because you are now familiar with the major A/C System items/components and their locations, let’s run down a short list of things to check before you call you call a technician.

These are super easy!

#1 – Check the Air Conditioner Thermostat

  • No air blowing at all – is the system turned on? Is there power to the thermostat?
  • Only warm/ambient air blowing – make sure the system is on COOL and not FAN, or HEAT.
  • If everything looks OK, check the power supply (electricity) next.

#2 – Check the Main Breaker Panel

  1. First, open the Main Breaker Panel
  2. Locate the breakers for the A/C AIR HANDLER and A/C CONDENSER UNIT  (likely “double” breakers as shown here, and 20-30A) – SEE RED [X] below.Air Conditioning Repair - 200A AC Breakers
  3. Flip each breaker to the LEFT (off) and back to the RIGHT (on). This will make sure the breaker hasn’t “tripped” or malfunctioned. As a result, the breaker should stay engaged and locked to the RIGHT after you reset it.
  4. Finally, if everything looks OK at the panel, check the power to the A/C Condenser, next.

#3 – Check the A/C Condenser Service Lockout Switch

  1. First, locate the A/C Condenser Lockout Switch.
  2. Open the A/C Condenser Service Lockout Switch cover Air Conditioning Repair - AC COndenser Service Lockout Switch
  3. IMPORTANT – Read the instructions, make sure the switch is NOT loose, AND pushed all the way in/firmly secure. Also make sure that it is not accidentally “locked out” (removed, inverted upside down, and reinstalled) –  to cut the power to the condenser (outside) WITHOUT having to access the main breaker panel in the house, basement, etc.Air Conditioning Repair - Service Lockout Instructions

#4 – Check the Air Handler Wet Switch

  2. If it detects any water, it completely shuts down the system. First, locate the Air Handler Wet Switch (in the bottom drain pan).

  3. RED light = the bottom “felt” pad is WET from being in the path of normal condensation/water OR the air handler drain pan is flooded from a clogged drain.Air Conditioning Repair - Air Handler Wet Switch
  4. Clear the drain pan drain if needed.
  5. Dry the “felt” pad on the bottom of the Wet Switch with a hair dryer – takes about 2 minutesAir Conditioning Repair - Drying the Air Handler Wet Switch
  6. Once the “felt” pad is thoroughly dried, push the RESET button = GREEN light.Air Conditioning Repair - Reset the Wet Switch
  7. Re-position the Wet Switch out near the edge, inside the air handler drain pan.
  8. DONE – turn the thermostat back on and give the system about 10 minutes to complete the HOLD / RESTART sequence.
  9. Finally, if the outside A/C Condenser fan is running, you should have COLD air!Air Conditioner Condenser


AIR CONDITIONING REPAIR – Help! It Still Does Not Work

Above all, if you have tried all 4 DIY tips above and you’re A/C is still not working properly, it may be time to call a HVAC professional. Rather, your additional issues may be:

  • Refrigerant (Freon) leak.
  • Mechanical component problem or failure inside the A/C Condenser OR Air Handler Unit.
  • Electrical component problem or failure inside the A/C Condenser OR Air Handler Unit.


Air Conditioning Repair


NOTE – Electrical Hazard: When working on ANY electrical equipment, ALWAYS make sure the main power source is unplugged / switched OFF / locked out BEFORE service or repair is attempted.


AIR CONDITIONING REPAIR – Additional Resources

What is a Wet Switch?

Main Breaker Panel Info

For More Old House Air Conditioning Info

Why The Unico System Air Conditioner & Your Old House Are a Perfect Fit








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