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Cleaning suggestions for the indoor air handler of split system air conditioners, window air conditioners, and through-wall air conditioners & heat pumps.
This article describes simple cleaning procedures to remove mold from the air path of window or wall mounted indoor air conditioning or heat pump units.
This article series describes split system air conditioning & heat pump systems. We review the major system components, switches & controls, and typical applications for split system cooling systems. We also discuss use of the remote thermostat control, where to find and how to clean the split system air filters, how condensate is disposed-of, and what to check first if your split system air conditioner is not working properly.
Cleaning Mold from a Wall or Window-Mounted Air Conditioner
These air conditioner mold removal steps will work on most window or through-wall air conditioners as well as on wall-mounted split system air conditioners and heat pumps. A split system or "ductless" air conditioning (or A/C & heat pump) system dispenses with duct
work entirely, using a wall-mounted indoor evaporator/blower unit and a separate outside compressor/condenser (below left and right).
[Click to enlarge any image]
At above left you can see rather typical dark mold growth on the plastic surfaces of the indoor half of a wall-mounted split system air conditioner. Similar mold may appear on window or through-wall mounted air conditioners as well. Mold grows readily on the plastic surfaces of the air conditioner's face cover and on its air-directing louvers because these surfaces often are damp with condensate from the conditioned air.
Mold may also grow on the metallic surfaces of the squirrel cage fan that blows room air through the air conditioner, more so as those surfaces accumulate building dust that typically includes organic debris such as skin cells.
At left is a close-up of a fairly-clean split system air conditioner blower fan. If you click to enlarge the image you'll see normal dust accumulation on the blade edges. In contrast, if the curved blades have become dust-laden not only does that serve as possible mold food it also means that the air-flow of the blower fan will be reduced.
Don't panic if you see some black mold or dark brown mold in the blower portion of your wall-mounted split system air conditioner. Most commonly the fungus is a member of the Cladosporium sp. family (among those samples we've tested in our lab).
Molds found in buildings may be relatively harmless, or allergenic, or sometimes more seriously harmful. Health risks are greater for people at extra risk themselves such as asthmatics, people suffering from allergies, the elderly, infants, and people with a compromised immune system.
It is normal for dust and debris to collect on the fins of air conditioner air direction louvers, grilles, and squirrel cage blower fans. Typically this is harmless house dust and it's not a problem until it obstructs air flow.
Below is a fairly dirty air conditioner air outlet grille or fan blade.
But if the air conditioner is frequently wet, for example from condensate, that same dust can host the growth of a variety of molds, many of which are not highly dangerous.
However depending on the surface material that has been wet, sometimes different and more troublesome mold genera/species may grow. And if such areas in the building are large (more than 30 sq .ft. of contiguous mold) or if harmful molds are in the air path of building air handlers such as air conditioners, professional cleaning may be in order.
See MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD if your building has a significant mold problem.
All of these surfaces can be cleaned if you work carefully to avoid damaging cooling coil fins or knocking about the wall mounted unit and its components. You'll need some household spray cleaner (any cleaner will work but avoid using corrosive cleaners or agents on metal parts and avoid spraying your eyes). You'll also want some clean rags or paper towels and a clean soft bristle paint brush.
Remove the plastic cover for the air conditioner and for best results, use your spray cleaner, paint brush, and a garden hose sprayer outdoors to clean the cover and its louvers. You can do that job indoors too at a large kitchen sink. Now while the air conditioner's cover is drying there is more mold cleaning to do.
Watch out: be sure that electrical power is off and disconnected from your air conditioner before removing its cover for cleaning or service. Otherwise you risk death by electrocution or cut or amputated fingers by moving parts should the equipment start while you're messing with it.
While the covers are off of the indoor air handler unit of a split system air conditioner, if you take care not to bend or damage any components, the use of a simple household spray cleaner, paper towels, and a paint brush can clean out most of the mold that likes to grow on these frequently-damp surfaces in the air conditioner's room-air path.
Using spray cleaner and dry paper towels we sprayed and wiped clean the easily-accessible areas of the wall-mounted air handler's surfaces taking care not to move, disturb, or break any louvers or other components. You can see the black mold on our paper towel at above left.
We also used a household-cleaner to wet our long soft bristle paint brush that in turn was used to gently clean the louvers of the blower fan (above right). Rinse the paint brush in clean running water, wet it again, and go back to continue cleaning the louvers of the squirrel cage blower fan until accumulated dust and debris have been removed.
Watch out: take care not to spray or wet electrical components, and avoid spraying or wetting any fan bearings or you may be sorry you undertook this step.
Watch out: if the cooling coil itself is badly soiled or blocked with dust and debris at your air conditioner or heat pump that tells us two things:
You should as for cleaning help from a professional who can probably get the job done faster, more completely, at lower cost, and with less risk of damaging the equipment than if you mess with it yourself.
You have not been cleaning the unit's air filter as frequently as you should.
At above-left is rather typical dark mold growth on the plastic components of a wall-mounted air conditioner.
This mold growth is small in total area, is not deserving of panic, and would be of only trivial concern were it not in the air path of an air conditioner that circulates room air. You indeed might want to clean the system using the methods described in the article above, particularly if there are building indoor air quality complaints that appear to correlate with operation of the air conditioner.
Questions & answers or comments about split system air conditioner operation, installation, maintenance, & repair
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: email@example.com or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions.
HVAC brands discussed here include but are not limited to: Lennox, American Standard, Amana, Everrest, Goodman, Frigidaire, Coleman and Gibson. Brands of related air handling equipment
include Honeywell, Aprilaire, White-Rogers, Broan. Nutone, Fantech, Venmar, Arzel, Hi-Velocity, Vanguard, Wirsbo, Weil McLain, Unico, Heat Link, A.O. Smith, Water Furnace, ClimateMaster, Geo-Excel, Command Aire, Friedrich, LG, Mitsubishi, Sanyo, Hart &
Cooley, Munchkin, Superstor Ultra, Lochinvar and Knight HVAC equipment.
HVAC Employment: U.S. Department of Labor website describes HVAC jobs and the employment outlook for HVAC technicians.
HVAC Education, Training Accreditation agencies: Quoting the U.S. DOL HVAC website above:: After completing the programs below, new technicians generally need between 6 months to 2 years of field experience before they are considered proficient. Three accrediting agencies have set academic standards for HVACR programs:
HVAC Excellence. 1701 Pennsylvania Ave NW,
Washington, DC 20006 Tel: (800) 394-5268. Quoting: HVAC Excellence is a not for profit organization that has been serving the HVACR industry since 1994. It is our goal to improve competency through validation of the technical education process. By setting standards and verifying that they have been met, we inspire the industry to excel. We know that all of the challenges that face our industry are achievable by continuous improvement in the way that we prepare technicians.
National Center for Construction Education and Research, 3600 NW 43rd Street, Bldg. G, Gainesville, FL 32606, Tel: 888.622.3720, Quoting:
NCCER is a not-for-profit education foundation created to develop industry-driven standardized craft training programs with portable credentials and help address the critical workforce shortage facing the construction industry.
The Partnership for Air-Conditioning, Heating, and Refrigeration Accreditation, (PAHRA)
2111 Wilson Blvd., Suite 500
Arlington, VA 22201-3001
(703) 524-8800, Quoting: The Partnership for Air-Conditioning, Heating, Refrigeration Accreditation (PAHRA) is an independent, third party organization that is a partnership between heating, ventilation, air-conditioning and refrigeration (HVACR) educators and the HVACR industry that will award accreditation to programs that have met and/or exceeded industry validated standards. This programmatic accreditation program is the only one that is supported by the major industry associations.
Licensure. Heating, air-conditioning, and refrigeration mechanics and installers are required to be licensed by some States and localities. Requirements for licensure vary greatly, but all States or localities that require a license have a test that must be passed. The contents of these tests vary by State or locality, with some requiring extensive knowledge of electrical codes and others focusing more on HVACR-specific knowledge. Completion of an apprenticeship program or 2 to 5 years of experience are also common requirements.
In addition, all technicians who purchase or work with refrigerants must be certified in their proper handling. To become certified to purchase and handle refrigerants, technicians must pass a written examination specific to the type of work in which they specialize. The three possible areas of certification are: Type I—servicing small appliances; Type II—high-pressure refrigerants; and Type III—low-pressure refrigerants. Exams are administered by organizations approved by the U.S. Environmental Protection Agency, such as trade schools, unions, contractor associations, or building groups.
HVAC Training Courses, Schools: HVAC Technician Training Schools [http://technicianschool.net/hvac-technician-training-schools/], lists the following schools offering technical courses may offer specific training programs for potential careers, including HVAC technicians. Among HVAC schools that website lists are
Everest Colleges [http://www.everest.edu],
Florida Career College
7891 Pines Blvd
Hollywood, FL 33024
2299 Vauxhall Road
Union, NJ 07083
NOTE: when considering an HVAC training course or school, check the HVAC education accrediting associations listed above.
 "Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]
 "Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and Refrigeration and Air Conditioning Technology, 5th Ed., William C. Whitman, William M. Johnson, John Tomczyk, Cengage Learning, 2005, ISBN 1401837654, 9781401837655 1324 pages
 "Falling Air-Conditioners Rattle Tenants", Chris Palmer, The New York Times, 2 July 2012, p. A12.
 Ratib Bakera is member of Refrigeration Service Engineers Society (RSES), an International
training organization for the HVACR industry provides educational and certification programs to HVACR professionals of all experience levels. www.rses.org provides information on the organization and its training materials. Independent testing and certification of HVAC technicians is provided by North American Technician Excellence - NATE - see www.natex.org.
NATE is supported by ASHRAE, the US EPA, and a host of other trade and professional associations.
 Singer brand HVAC equipment brand history: Singer was bought by & became the climate control unit of Dallas-based Snyder General Corp. (founded by a former Singer HVAC manager) in 1982. The name Singer was dropped in 1984. In 1984 Snyder General operations included Arcoaire, Comfortmaker, and McQuay. In 1991 Snyder General sold Arcoaire & Comfortmaker to Inter-City Products. In 1994 Snyder General was acquired by Hong Leong Group Malaysia. Snyder General is at 2001 Ross Avenue Dallas, TX 75201.
 Lennox air conditioning and heat pump owners manuals for air conditioners, air handlers, furnaces, heat pumps, indoor air quality systems, packaged units, water heaters, zone controls and other controls such as thermostats, are provided by Lennox at http://www.lennox.com/support/manuals.asp
 Troubleshooting Split System A/C or Heat Pump Noises, Fujitsu General America, Inc., 353 Route 46 West, Fairfield, NJ 07004, Tel: (888) 888-3424, Tel-Service hotline: (866) 952-8324, Email: firstname.lastname@example.org, Email service: email@example.com , retrieved 8/30/12, original source: http://www.fujitsugeneral.com/troubleshooting.htm [copy on file as Troubleshooting Fujitsu Ductless Mini-Splits.pdf]
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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