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 Mobile ViewAIR CONDITIONING & HEAT PUMP SYSTEMS A/C - HEAT PUMP CONTROLS & SWITCHES AGE of AIR CONDITIONERS & HEAT PUMPS AIR CONDITIONER BTU CHART AIR CONDITIONER COMPONENT PARTS Indoor A/C Components Outdoor A/C Components AIR CONDITIONER TYPES, ENERGY SOURCES AIR CONDITIONER NOT WORKING AIR FILTERS for HVAC SYSTEMS AIR HANDLER / BLOWER UNITS ADDING A/C: RETROFIT SIZING BLOWER FAN CONTINUOUS OPERATION BLOWER FAN OPERATION & TESTING BLOWER LEAKS, RUST & MOLD COOLING COIL or EVAPORATOR COIL DIRTY A/C BLOWERS ANIMAL ALLERGENS / PET DANDER ANIMAL ENTRY POINTS in buildings ANIMAL ODORS IN buildings APPLIANCE EFFICIENCY RATINGS ASBESTOS IDENTIFICATION IN buildings BACKUP HEAT for HEAT PUMPS BLOWER DOORS & AIR INFILTRATION BLOWER FAN CONTINUOUS OPERATION BLOWER FAN OPERATION & TESTING BOOKSTORE - Air Conditioning "How To" Books CAPACITORS for HARD STARTING MOTORS CAPILLARY TUBES CHINESE DRYWALL HAZARDS CIRCUIT BREAKER SIZE for A/C or HEAT PUMP CLEANING & Legionella BACTERIA COMBUSTION GASES & PARTICLE HAZARDS CONDENSATE HANDLING, A/C CONDENSATION or SWEATING PIPES, TANKS COMPRESSOR & CONDENSING COIL, A/C BURNED-OUT COMPRESSOR CAPACITORS for HARD STARTING MOTORS CONDENSING COIL REPAIR REPLACE CONTACTOR RELAY DIAGNOSIS & REPAIR CONTROL CIRCUIT BOARD, A/C FAN, COMPRESSOR/CONDENSER UNIT HARD STARTING COMPRESSOR MOTORS INSPECTION CHECKLIST - OUTDOOR UNIT INSTALLATION ERRORS, COMPRESSORS LEVELING REQUIREMENTS, COMPRESSOR LONG-ON CYCLING AC COMPRESSOR MOTOR OVERLOAD RESET SWITCH NOISES, COMPRESSOR CONDENSER Pressure Controls & Safety Switches PRESSURE READINGS, COMPRESSOR REPLACING A COMPRESSOR SHORT CYCLING AC COMPRESSOR TIGHT or SEIZED AC COMPRESSORS CONDENSATE HANDLING, A/C CONDENSATION or SWEATING PIPES, TANKS CONDENSING COIL COOL OFF HEAT Thermostat Switch COOLING CAPACITY, RATED COOLING COIL or EVAPORATOR COIL DAMAGED COOLING COIL DIRTY COOLING COIL DIRTY COIL CLEANING PROCEDURES FROST BUILD-UP on AIR CONDITIONER COILS DATA TAGS on AIR CONDITIONERS DEFINITION of Heating & Cooling Terms DEHUMIDIFICATION PROBLEMS DEW POINT CALCULATION for WALLS DEW POINT TABLE - CONDENSATION POINT GUIDE DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP DUCT SYSTEM & DUCT DEFECTS DUCTS - Asbestos DUCT INSULATION, Asbestos Paper DUCT INSULATION for SOUNDPROOFING DUCT SYSTEM NOISES DUCTS, Asbestos Transite Pipe DUST CONTAMINATION FROM HVAC? EDUCATION, HVAC SCHOOLS ELECTRIC MOTOR DIAGNOSTIC GUIDE ELECTRIC MOTOR OVERLOAD RESET SWITCH ELECTRICAL POWER SWITCH FOR HEAT EVAPORATIVE COOLING SYSTEMS EVAPORATOR COIL or COOLING COIL EXPANSION VALVES, REFRIGERANT FAN, AIR HANDLER BLOWER UNIT FAN AUTO ON Thermostat Switch FAN, COMPRESSOR/CONDENSER UNIT FAN CONVECTOR HEATERS - HYDRONIC COILS FAN LIMIT SWITCH FAN NOISES FURNACES WARM AIR HEATING SYSTEMS GAS EXPOSURE EFFECTS, TOXIC GAS DETECTION & MEASUREMENT GAUGE, REFRIGERATION PRESSURE TEST HEAT LOSS (or GAIN) in buildings HEAT LOSS (or GAIN) INDICATORS HEAT LOSS R U & K VALUE CALCULATION HEAT PUMPS HEATING SMALL LOADS HOUSEWRAP AIR & VAPOR BARRIERS HUMIDITY LEVEL TARGET INDOOR AIR QUALITY IMPROVEMENT GUIDE INSPECTION CHECKLIST - OUTDOOR UNIT INSPECTION LIMITATIONS, A/C SYSTEMS LEED GREEN BUILDING CERTIFICATION LOST COOLING CAPACITY What to Check First A/C Flow Too Weak A/C Filter Problems A/C Compressor Problems A/C Off - Condensate Pan Switch A/C Cooling Coil Icing A/C Not Dehumidifying A/C Air Duct Problems Air Conditioner Won't Start Air Conditioner Refrigerant Problems Blower Fan No Start / No Stop Compressor Diagnosis: Diagnose & Repair Cooling Capacity of the Duct System Repair Guide Master List MANUALS & PARTS GUIDES - HVAC MOTOR OVERLOAD RESET SWITCH MOLD in AIR HANDLERS & DUCT WORK ODORS in AIR HANDLERS & DUCT WORK OPERATING COST OPERATING DEFECTS OPERATING TEMPERATURES Air Conditioning System Temperatures Instruments Used to Measure A/C Temperatures Procedures for Making Temperature Measurements PORTABLE ROOM AIR CONDITIONERS PRESSURE READINGS, REFRIGERANT REPAIR GUIDE, AIR CONDITIONERS / HEAT PUMPS REPAIR & DIAGNOSTIC FAQs for A/C REFRIGERANTS GAUGE, REFRIGERATION PRESSURE TEST REFRIGERANT CHARGING PROCEDURE REFRIGERANT DRIERS & FILTERS REFRIGERANT LEAK DETECTION REFRIGERANT LEAK REPAIR REFRIGERANT METERING DEVICES TEVs REFRIGERANT METERING CAPILLARY TUBES REFRIGERANT PIPING & DISTANCES REFRIGERANT PRESSURE READINGS RETROFIT SIZING for A/C or HEAT PUMPS SEER RATINGS & OTHER DEFINITIONS SOLAR ENERGY SYSTEMS SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS SWAMP COOLERS SYSTEM OPERATION THERMOSTATS, HEATING / COOLING THERMOSTATIC EXPANSION VALVES WATER COOLED AIR CONDITIONERS More Information |
This article discusses the how the cooling coil (evaporator coil) in the air conditioning air handler unit is cleaned. These same methods will work on the outdoor coil or condensing coil as well. Our photo at page top shows a very dirty cooling coil in the attic air handler component of a central air conditioning system. If your air conditioning or heat pump system has lost its cooling capacity or won't start see REPAIR GUIDE for AIR CONDITIONERS. See How to determine the cooling capacity of air conditioning equipment if the system seems to be working but is inadequate to cool your building. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. How & Why Air Conditioning & Heat Pump Evaporator Coils (Cooling coils) are CleanedWhich Cooling or Heat Pump "Coil" is Which: Condensing Coil & Cooling/Evaporator Coils DefinedThe COOLING COIL or EVAPORATOR COIL discussed here is the evaporator coil found inside the air handler, used to cool air blown across it and into the building occupied space. If your concern is with If your equipment is a heat pump these terms can be a bit confusing because in heating mode, your heat pump system's indoor coil is warming, not cooling the air blown across it The CONDENSING COIL is normally on the outdoor or compressor portion of your air conditioning system. The job of the condensing coil is to cool high temperature refrigerant gas to condense it back to a liquid refrigerant form. Why do we clean the HVAC evaporator or cooling coil, or the condenser coil?Dirt and debris accumulating on an air conditioner or heat pump coil block airflow across the coil, increasing the cost of heating or cooling the building. In severe cases cooling or condensing coils can become so blocked that air flow is seriously reduced, possibly also leading to an evaporator or cooling coil icing problem indoors or an overheated, damaged compressor outdoors, or simply loss of cooling capacity of the system. In addition, a blocked evaporator coil can cause the HVAC compressor to run at higher than normal temperatures - a condition that over time can break down lubricants circulating inside the system, thus shortening the life of the compressor motor itself. BLOCKED COOLING COIL - Air Conditioner Evaporator Coil Blocked by Debris There was no air filter installed in the system. Ordinary house dust is comprised largely of fabric fibers and skin cells. These and other debris in building dust such as soot and organic particles like pollen and mold spores all join to form a gray mat on the fins of the cooling coil in an air handler. Debris sticks particularly quickly to this surface because of the combination of close spacing of the cooling fins (about 1/16" apart) and the fact that condensate forming on the coil keeps the surface damp. Details about the detection and cleaning of dirt and debris which block an air conditioner cooling coil are at DIRTY COOLING COIL. Guide to Procedures for Cleaning Air Conditioner or Heat Pump Evaporator Coils: Using Air, Brushes, Chemicals, or Detergents to Clean A/C CoilsThorough cooling coil or A/C evaporator coil cleaning can require cutting refrigerant lines, removal of the coil and other components for cleaning, and reinstallation, pulling a vacuum on the refrigerant lines, and recharge with refrigerant. Such service and repair may involve significant expense. For this reason there are several "in place" cleaning methods using foams and sprays that are a simpler procedure for cleaning an air conditioning or heat pump coil. Watch out: be sure that electrical power is off to the HVAC equipment before opening access panels or working on the system. Relying only on the door safety interlock switch to turn off equipment power may be unsafe as wiring inside the unit will still be "live" in some locations. Using Air: Compressed air for cleaning HVAC evaporator coilsSome HVAC technicians clean an evaporator coil by blowing it off with compressed air. This is a quick and probably effective method to clean the coil, which has the additional feature of blowing dust, debris, and possibly mold into the building air - not something we approve. Air is sprayed from the cleaner side of the coil towards the dirty side - or in other words, in the opposite direction from the normal air flow across the coil. Be sure to spray from the correct side of the coil or you'll just be forcing dirt and debris more deeply into the coil fins. Watch out: if you are using high pressure air to try to clean a coil, be sure you blow air at right-angles or straight through the coil fins. Blowing high pressure air (or water or steam) at the HVAC coil fins on an angle is likely to bend over the fins, clogging the coil and possibly ruining it. If just a few fins have been bent on a coil they can often be straightened by working gently with an HVAC coil comb designed for that purpose. Watch out: if you are not careful, just using compressed air to blow off a coil may leave a large amount of dust and debris inside the air handler where it collects anew on coil surfaces, or in your eyes (dangerous). Using a shop vac in concert with the compressed air sprayer and moving carefully (to avoid damaging coil fins) can reduce dust and debris spillover and make cleaning up easier. Condenser coil cleaning: We don't have a complaint about using compressed air to clean an outdoor evaporator coil since we don't have the same concern about blowing debris into the building or its duct work. Brush-cleaning of A/C or heat pump cooling or heating coilsWhen the coil is soiled by a fairly light coating of dust and debris, it can often be successfully cleaned using a soft brush. If you clean you A/C or heat pump coil every three or four months using this method you may reduce cooling (or heating) costs and you may be able to avoid more costly or troublesome coil cleaning procedures. If your HVAC equipment is operating in a dusty area or if no one has been maintaining proper filters in the system it is likely that you'll need to clean the coil more frequently, perhaps even monthly to keep the A/C or heat pump system at peak operating efficiency and effectiveness. We have tried using a shop vac with a soft brush attachment to clean the A/C coils, but if your coil is mounted in the air handler so as to not leave much room to access all of its surface this approach doesn't work well. Watch out to avoid damaging coil fins when using any tools, brushes, or vacuum cleaners around the equipment. Using Chemicals to Clean A/C CoilsThere are plenty of coil cleaning chemicals sold for cleaning A/C or heat pump systems, both acid and alkaline-based. Watch out: We do not recommend using strong chemicals on an A/C or heat pump coil because of the risk of corrosion damage to the coil or the production of noxious odors & fumes. To be safe, check with your HVAC equipment manufacturer to be sure that your cleaning approach is one they approve. Field Report: Using Hydrogen Peroxide to Clean an HVAC Coil?
While we have read reports that the oxide on the surface of aluminum HVAC coil parts reduces the severity of chemical reaction between an acid or base cleaner and the metal, we have also had reports of problems with corrosion and odors when this approach was tried. So while the "bubbling" action of hydrogen peroxide is appealing as a cleaner, we are warned that chemical reactions between some coil cleaning products and the aluminum or copper A/C or heat pump coil parts can corrode the fins or tubing, damaging the system, ultimately leading to leaks and the need for a costly coil replacement. Chemical reactions between some coil cleaning products and the aluminum or copper A/C or heat pump coil parts can also produce obnoxious odors or fumes, possibly toxic or irritating fumes, and in some cases may leave an odor in the system that itself becomes an issue. See our discussion of detergents and foam sprays for coil cleaning, below - those are safer approaches to coil cleaning, especially if you're not an expert. Using Detergents or Water for cleaning A/C coilsUsing a simple hand sprayer or garden sprayer (these produce a gentle spray) it may be possible to clean your A/C or heat pump coil effectively using tap water or a mild detergent. The advantage of using these gentle solutions is that there is little risk of damaging the coil fins or tubing compared with the use of more harsh chemicals. Wet the A/C or heat pump coil surfaces with your spray-on detergent, let it soak in for 15 minutes or so (but not long enough to dry out), then rinse the coil and coil fins clean. Remove spillover and debris from the condensate pan where your spray and debris land, using a shop vac or hand wiping. Watch out: don't bang around inside the air handler with your shop vac or you may damage the evaporator/cooling coil or coil fins; and be careful when wiping by hand that you don't get cut on sharp fin edges. If using water or a non-sudsing mild detergent doesn't work to clean off your coil, you may need to use a more aggressive coil cleaning method such as those described below. Using Foam or spray HVAC coil and fin cleanersUsing a garden sprayer (or a sprayer that may be included in some pre-packaged A/C coil cleaning systems and products), the coils are sprayed with a foaming cleaner specifically designed for HVAC systems. An advantage of this approach is that it is mechanically gentle, reducing the risk of damage to the coil or its fins. And if you select a benign cleaner it is also chemically gentle, avoiding corrosion damage to the coil. Where to Buy HVAC and Refrigeration Equipment Coil Cleaning ProductsList of HVAC coil cleaning chemicals and sprays:
The HVAC coil spray approach has the appeal that the total cleaning cost is low, no rinsing is necessary with some products, and the coil looks nice. Where does the debris and run-off cleaner go? It should drip into the condensate pan for disposal through the condensate drain system. The manufacturer says the coil and fin cleaner also removes odors from the system, but if your HVAC system is quite dirty additional steps will be needed to clean the blower assembly and the ductwork. After the coil cleaning foam has worked on the coil surfaces and dripped to the condensate pan below, use a wet-dry shop vac to clean up the mess from the pan, followed by careful wiping as we cited above. Using Pressure Washers to Clean A/C or Heat Pump Coil Fins & TubingProfessional HVAC service companies often use a portable A/C coil pressure washer designed for that purpose. Unlike cleaning detergents or foams, a pressure washer is physically more aggressive coil cleaning method and is perhaps the most thorough or effective method for cleaning a badly soiled or blocked HVAC evaporator or condenser coil. A portable pressure washer unit such as Goodway's CC-140 contains both a coil cleaning solution (typically a detergent mix) and a battery-operated pressure sprayer that can deliver as much as 140 psi. Heavier-duty coil cleaning pressure sprayers are available for commercial units and larger, or heavier, wider coils. Watch out: as we warned earlier, if you are using high pressure air, water, or steam to try to clean a coil, be sure you blow air at right-angles or straight through the coil fins. Blowing high pressure air (or water or steam) at the HVAC coil fins on an angle is likely to bend over the coil fins. And don't over-do it and don't spray more cleaner than needed - you'll just have more liquid cleanup to do after the coil has been treated. Using Steam-Cleaning of A/C or Heat Pump CoilsSteam is used by some technicians to clean HVAC coils, in a process similar to that we described above for compressed air. Watch out: as we warned earlier, if you are using high pressure air, water, or steam to try to clean a coil, be sure you blow air at right-angles or straight through the coil fins. Blowing high pressure air (or water or steam) at the HVAC coil fins on an angle is likely to bend over the coil fins. Questions & Answers regarding this articleQuestions & answers about cleaning methods for air conditioner or heat pump cooling and condensing coils Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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