HVAC Tech recommends acid wash - Yes or No?

Old 06-04-08, 11:09 AM
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HVAC Tech recommends acid wash - Yes or No?

A HVAC tech inspected my A/C which does not blow cold air. Everything else works (fan blows, no leaks, water flows, etc.). I live in a condo and the building's outside unit is in proper condition. Tech recommends an acid wash ($350). Is this something I can do myself? Is it necessary? Other recommendations?
Old 06-04-08, 11:36 AM
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By acid wash I imagine he means a thorough cleaning of the outdoor coil.

You can do this yourself. If so, you first wet the coil with water (and a garden hose), buy an outdoor coil foaming/cleaning solution (for hvac application) which you will spray generously around the fin&tube assembly...let it seat for a few minutes, see the dirt foam/bubble-up, then follow it by a thorough water spraying of the finned-coil to wash-out all the chemical. A pressure washer is best, but a garden hose suffices since the solution does a fine job.

Make sure you do not get any electrical components wet.

I buy my supplies at Johnstone Supply, but have been told that the home depot now sells this cleaning solution. Make sure is for outdoor coils, for hvac applications, and is of the foaming type. You DO NOT want to use this same solution for the indoor coil (if you decide to do the indoor too, which is not really necessary)...the smell is way too pungent.
Old 06-04-08, 12:34 PM
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Just a word of warning I have used a pressure washer for coil cleaning but if you decide to use a pressure washer you CAN severly damage the coil fins, you can easily bend the little fins flat and then spend many hours with a fin comb cussing your luck. A regular water hose wih a standard spray end is usually sufficent the chemical does most of the cleaning the water is just to remove the chemical and dirt after it is loosened. The condensing coil cleaning chemical (I like the Foaminator) is strong and a thorough rinse is required, any solution left on the coils will eat them away over time, be sure and read the directions on the container. The Evaporator coil cleaner is a different formulation with most being a nonrinse type simply spray it on liberally and gently brush with a medium to soft nylon bristle brush, then run the unit and the condensate running down the coil will rinse the residue away. Lots of different formulations out there, some are basically worthless (tree hugger type) some are darn good (highly alkaline and dangerous). Some panel removal is typically required to properly access the coil for cleaning since you need to rinse form the inside out. It is not just a matter of waving the garden sprayer and then rinsing lol, however the task should be well within the capabilities of any determined DIYer. A jug of the good stuff should be under 20 bucks, you will need some hand tools for panel removal/proper Personal Protective Equipment safety glasses etc/garden sprayer to apply the chemical and a water hose to rinse it with. Keep your kids and pets away and have fun.

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