In the early 1990’s, I bought a home in south Florida and did the usual routine of hiring a Home Inspection company. Home Inspectors are worth every penny and among the many items they examine, will check the heating and cooling operation of the air conditioning units – air temperatures and general condition of the unit. You should confirm in advance the Inspector will open up air handler to check the condition of the blower fan, evaporator coils, drain pan, etc. The Home Inspector that I hired back then didn’t open up the air handler and I wasn’t knowledgeable enough back then to ask about it.
When buying that home in south Florida, I made the expensive mistake of not hiring an air conditioning technician to open up and inspect the air handler before I purchased that home in south Florida. Rather, I hired an A/C company to check the unit after I closed the deal and was moving into the home. When the A/C technician opened up the air handler he called me over and said the unit had never been serviced and was a mess. The evaporator coils were covered with mold, heavily rusted and leaking refrigerant. I had the A/C company replace the entire air handler that very day to the tune of $1,700.00.
This is the attic air handler in my current home.
Attic Air Handler - Furnace and Air Conditioner Evaporator Unit
Having learned my $$$ lesson, I always hired a Home Inspector and a HVAC technician to inspect a new home and the HVAC system.
Routine Maintenance
Routine inspection and maintenance is very important to catch problems and save on your electric bill. I recommend hiring an HVAC technician to inspect and maintain the system twice a year; Spring and Fall are best before the summer or winter season begins and you really need your system.
The most important thing a home owner should do is regularly change the air filter. I installed touchscreen 7-day programmable digital thermostats by Honeywell that reminds me when it’s time to change the air filter. A clogged air filter will drive up your electric bill as the system struggles to heat or cool your home.
Other things a careful and knowledgeable homeowner can do is clean the evaporator coils and condenser coils. If you’re not comfortable in doing this yourself, at least you’ll know when to call a professional.
What’s that Thing in the Attic?
This is a the air handler in my attic. It is known as an “upflow” type because air enters from the bottom and exits out the top. The unit combines a natural gas furnace and an air conditioning evaporator coil. It has three major sections:
- Blower motor – bottom
- Gas furnace – center
- A/C evaporator coil – top
The entire air handler sits on a secondary drain pan with a cutoff float switch. The purpose of the secondary drain pan is catch water in case the condensate drain line becomes clogged or the main condensate pan rusts through. The secondary pan will catch the water and eventually activate the float switch to shut down the entire unit before it overflows and ruins the ceiling. Too often, the secondary drain pan becomes rusty and fails to hold the water.
Click on the image for a full size view.
Attic Air Handler
Remove the Evaporator Coil Access Panel
Before you begin, turn off the A/C at the thermostat.
This is a closeup of the evaporator coil access panel. It’s held in place by nine 1/4 inch sheet metal screws and sealed along the bottom with metal foil tape.
Evaporator Coil Housing
Remove the access panel screws with a socket wrench and peel away the metal foil tape along the panel edges (if any).
Removing the Access Panel Screws
The access panel is removed exposing the air conditioner evaporator coils. The evaporator coils are basically a heat exchanger, cooling the air inside the house and transferring the heat to the outside condenser unit.
Evaporator Coils and Access Panel
A-Frame Evaporator Coil
My unit has what’s known as an A-frame style evaporator coil. The coil has a two halves joined together like the letter A and sits on a condensate drip pan. The drip pan forms a moat under the coils to catch the water dripping down as warm humid air from the house is chilled as it moves across the cold coils. The bottom of the A-frame is open so the air can flow through.
A-Frame Evaporator Coil
The better evaporator coils have a plastic condensate pan to that won’t rust through. If the condensate pan were to develop a leak – or the condensate drain were to get clogged up, the water will do one of two things:
- Overflow and pool in the safety condensate pan under the whole unit, which will eventually fill up and trip the safety float switch, shutting down the unit. The purpose of the float switch is to prevent the pan from overflowing and causing water damage to the ceiling and rooms below.
- If the unit doesn’t have a safety pan under the unit, you’ll have water damage right away.
On a typical summer day, the evaporator coils can generate gallons of condensate water as it dries and cools the air inside the home.
This article is continued in Part 2.
Take care,
Bob Jackson
July 14th, 2009 at 8:30 pm
Thanks for providing this information to your readers. This would really give them a helping hand to learn more and would give them idea on how to clean their own air conditioners at home.
August 21st, 2009 at 11:03 pm
Hello,
Thanks for this information. Gave me the confidence to inspect mine and clean them. They were absolutely filthy! I never imagined they would be after just 8 years.
THANKS!!!
Ray Winter
January 4th, 2010 at 6:42 pm
if i use the frost king cleaner in the winter, will i need to rinse?
January 4th, 2010 at 7:54 pm
I think your concerned about the A/C being shut off in the winter and therefore no water condensation to further rinse the coils as there would be in the summer when the system is running. The instructions say it’s a “no rinse” product and I didn’t see disclaimers about seasonal/winter use. The foam breaks down nicely and drains away. You might shut off the heat for an hour so the fluid can do its work.
A second application at the start of summer wouldn’t hurt if in doubt.