What Do We Check Indoors on an AC Check?

Every air conditioner needs routine maintenance and periodic tune-ups. Most of the issues with AC units have to do with the condenser, or the outdoor unit. But the indoor unit can have its own set of issues. That’s what we want to discuss in this post, what the issues are, and how we try to prevent them with our basic AC check.

Anatomy of the indoor unit…

The indoor unit, as it pertains to your air conditioner, is made up of the… 

  • Evaporator coil 
  • Primary drain pan
  • Condensate drains 
  • Jones valve
  • Ceiling Saver Float switch
  • Auxiliary/emergency drain pan 
  • Blower motor

How it Works

The blower motor pulls air from inside the home, across the evaporator coil (that is around 38-40 degrees), and then circulates it through the ductwork into the home. As air passes over the evaporator coil the moisture in the air condensates on the coil and runs down into the primary drain pan where it is directed down the primary drain.

Evaporator Coil

The evaporator coil is where the transfer of heat takes place, cooling the air in your home. When your AC is running the evaporator coil is 35-45 degrees and wet due to condensation. When it’s off the coil is warm and dry. This makes a great home for bacteria and other organic growth. This is why we treat the coil if we can access it. When we do a tune up on your system we treat the evaporator coil with an enzymatic cleaner that leaves enzymes on the coil to eat organic growth for up to 6 months.

Primary Drain Pan

As water condenses on the evaporator coil it runs down the metal fins and into a large pan directly beneath the coil. This is the primary drain pan. You can’t typically see this pan, it’s inside the air handler cabinet with the coil. 

We generally have two concerns when it comes to the primary drain pan. First, is the unit level for draining, and second, is there any standing water in the primary drain pan?

Level for Draining

Everything can be connected and operating properly but if the unit isn’t leveled so that the drain exit is the low point, then the condensation won’t drain, and the unit could flood. This is why we check if the unit is level for draining on every AC check and AC tune up

Standing Water

We then look for standing water in the primary pan. Standing water can become a breeding ground for bacteria, algae, and other organic growth. To help combat this we put tablets into the pan to help kill and eradicate the organic growth.

Condensate Drains

Connected to the primary drain pan are two drain lines, the primary and the secondary. The primary drain connects to a drain in your home and the secondary terminates outside. If the primary clogs then the water routes to the secondary and drips outside where you can see it.

To help prevent clogs we pour bleach down the drain line and use a brush to clean the p-trap if you have one.

Drain Blow Out Valve

Since 2018 it has been code that the primary drain line have a means to pressurize the line to remove clogs that doesn’t require the technician to cut the drain line. If you have a blow out valve we will blow out your drains on each AC check. If you don’t have one we will let you know and ask if you’d like us to install one.

Ceiling Saver Float Switch

Since 2010 it has also been code that the drain system have a float switch on the secondary drain within 6 inches of the coil. The purpose of this switch is to shut the air conditioner off if the primary and secondary drains both back up. This way the system doesn’t overflow and flood your home.

Every time we do an AC check we look to confirm that you have a float switch and also that it works. If you don’t have one or it isn’t working we will let you know so we can get it resolved and keep your home safe from flooding.

Auxiliary/Emergency Drain Pan  

Outside the air handler cabinet and underneath the evaporator coil is another drain pan. This is the auxiliary drain pan, or emergency drain pan. If all else fails this is supposed to catch the water and direct it outside via the secondary drain. We check this pan to make sure it is dry, and also to make sure it is also level for draining.

Blower Motor

After all those checks we make sure the blower motor and its components are also operating as designed. We also clean the blower wheel in place with a foam cleaner to help maintain the blower’s efficiency. Most people don’t realize that 1/16” of dust build up on the blower wheel can reduce its capacity up to 30%. Keeping it clean is incredibly important.

Air Handler Cabinet

Finally, when we’ve completed all this we sanitize the inside of the cabinet to help prevent future growth. We spray down the inside with a hospital grade sanitizer that coats and cleans the inside walls of the air handler.

This is a quick summary of the work we do on the indoor unit for every AC check and AC tune up.

Choose Prestige Air to Keep Your HVAC Running Optimally

If you experience problems with your heating and cooling call Prestige Air. Our expert service professionals have the training and experience to keep your HVAC system in tip-top shape all year long. Call (817) 200-7215 to make sure your heating and cooling are ready for the season!

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At ​Prestige Air, we’re a team full of passionate heating and air conditioning technicians who care deeply about our clients. We know that issues with your heating and cooling can be a headache and our goal is to get your issues resolved ASAP so you can get back to living your life stress-free.

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