How to clean internal evaporator coils?

Question

I opened the duct work to my evaporator coils and seen them frozen. This is causing the A/C to run all day with little air flow seen at the vents. Do you know of cleaning solutions that can be bought from a store (eg Homedepot). Also, do you clean the unit in place? Do you scrape it, etc.

Answer 1

First shut off the AC and let the ice melt off of the AC coil. Second CHANGE your AIR FILTER (I worked 14 years in the HVAC field and this is the largest source of icing problems) check to make sure all of the vents are open on your registers (another air flow issue I commonly found) and are unobstructed. Once the coil has thawed out you can check to see if there is lint and dirt built up on the coil. If it is dirty use a plastic scrub brush and pull with the fins to get the dirt off. you can gently spray the coil with water to help get the crap off too. as far as a chemical to help clean it I would suggest CLR (dont go out and get an acid to give the coil a bath because I've seen too many not get rinsed out enough and eat through) just remember to rinse the coil really well if you use a chemical. hose out the coils on the outdoor unit (condenser). put it all together again and try it. if it ices up again i would suggest calling a reputible servce company to have the refrigerant checked.

whatever you do DONT scrape or pound on the coil (drive a screwdriver into the ice) if you do you'l be bying a new AC system. It can be cleaned in place most of the time, if it needs removed a liscensed contractor will need to do that (for dealing with the refrigerant in the system)

Answer 2

Evaporator Coil Cleaner

Answer 3

DO NOT let anyone add freon to to your A/C until that evaporator coil is clean. Chances are good you would end up with an overcharged unit, very tough on the compressor and your electric bill. First you need to thaw and dry the coils by turning the A/C off and the fan on at the thermostat. This may take a couple hours or a half a day depending on the ice buildup. How to clean varies depending on the type of dirt, some turns to dust and you can brush and blow it out against the direction of airflow, or wash it out with a garden hose. Some is like 'dryer lint' and sometimes you can lift it off in one piece to reveal a clean coil, or use a hairbrush to gently roll the lint out. It can also be any combination of the two. In this case do the lint thing first then the dust thing. Save the coil cleaners to the pros, I only use it in restaurants and manufacturing plants with grease in the air. Now after cleaning the coil the evaporator still ices call the repairman. RScott

Answer 4

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RE:
How to clean internal evaporator coils?
I opened the duct work to my evaporator coils and seen them frozen. This is causing the A/C to run all day with little air flow seen at the vents. Do you know of cleaning solutions that can be bought from a store (eg Homedepot). Also, do you clean the unit in place? Do you scrape it, etc.

Answer 5

NEVER SCRAPE YOUR COILS, unless you want to buy a new one.

Change your filter.

Is the indoor fan running on high?

You can use a gentle brush to sweep dust and lint off of the coils off in the direction of the fins.

Once you have brushed off the dust, go to the hardware store and look for coil cleaner or make a solution of 1 part dishwasher liquid (dawn is a good one, but any will do) and 9 parts water. Put this solution in a spray bottle. Turn off your A/C and fan. Spray the solution on the coil soaking the entire coil. Let it sit for a few minutes then rinse with clear water. The water should run down the coil and out the condensate drain.

Start up the A/C and close the door. After it has run for five to 10 minutes, get a thermometer and measure the air temperature of air going in compared to air coming out. The air out should be around 20* (+/- 2*) cooler. If not, call the repair company.

Answer 6

The evaporator coils freezing up is a strong indication that your freon charge is low. Get that taken care of first. To clean the coils, there is a spray on -coil-kleen' or similar solution that you just spray on and rinse off after allowing it to dissolve any dirt. If your filters are in good shape and changed regularly, you should never have to use coil cleaner more often than every 5 years. It is a mild acid and can eat through an aluminum evaporator if left on too long.

Answer 7

Use a wire brush to lightly remove any surface dirt or debris. Be careful not to bend the coil fins over. There is a product called "simple green" you can find it at home depot. This is a great cleaner. We use it all of the time in commercial HVAC for cleaning coils. If it is really dirty you can use an air compressor. This can be messy, but it does work. Good luck.