Gas and Oil Home Heating Furnaces - Cleaning the coil

The evaporator coil on my AC unit is very dirty. A repairman told me to clean it he would need to cut the refrigerant lines, drain the coolant, remove the coil, and take it to a carwash where he would spray it out. The cost of this plus re-connecting the refrigerant lines, and adding new coolant was $400.

Is there any reason, why I shouldn't just drag a hose into my attic and clean it out myself, without removing the coil? If not, is there anything I need to be careful not to do? The tech said I may be able to do that, but he won't because he doesn't want to be liable for getting water on my sheetrock and causing additional damage.

Originally posted by MZW
The evaporator coil on my AC unit is very dirty. A repairman told me to clean it he would need to cut the refrigerant lines, drain the coolant, remove the coil, and take it to a carwash where he would spray it out. The cost of this plus re-connecting the refrigerant lines, and adding new coolant was $400.

Is there any reason, why I shouldn't just drag a hose into my attic and clean it out myself, without removing the coil? If not, is there anything I need to be careful not to do? The tech said I may be able to do that, but he won't because he doesn't want to be liable for getting water on my sheetrock and causing additional damage. If you want to try it yourself ,I sure would for that many $$$$$.In your setup we would use a coil cleaner and any kind of portable sprayer on the coil also a good wet dry vac would be handy.To start if the unit has been off for some time you can start with a fin brush to get the big stuff off keep the vac hose by the brush as you do it. After that spray the coil,with a coil cleaning and degreasing concentrate use it about 1-4 with water.Let it soak about 30 min. Then wash down with clear water. keep an eye on the drain pan so it dont run over ,use the vac .I have never heard of takeing a coil out to clean it. I will say over 6o% of all our service jobs of no cool end's up from dirt inside or out in the coils and ants in the relay's;) ED

Thanks for the info. By the way, where would I get the coil cleaner that you mentioned? What is the brand or name that you would recommend?

I almost always take coils out to clean them, but I sure don't take them to the car wash! I use an alkaline based foaming action cleaner that boils the dirt out of the depth of the coil. The dirt gets impacted into the coil over time and surface cleaning is insufficient. Also, I have to use a lot of water to rinse off all the coil cleaner. There are several brands around, RENEWZ is one name that comes to mind. You have to buy them at the commercial HVAC parts houses or maybe Graingers. However you decide to do the job, be sure to wear eye protection and HEAVY rubber gloves. Buy gloves for chemcals, not the ones that just prevent dishpan hands.

Pressure from the car wash spray wand will bend/ flatten the fins on the evap coil, making it worse than it is now (unless he stands 10 feet away) then, you might as well use a regular water hose. I've cleaned my coil with coil cleaner, stiff nylon brush, and a wet dry vac before, wasn't easy, a little messy, but worth the results.

Thanks to all for the info!