Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
Ask a Question or Search InspectAPedia
InspectAPedia ® Home
AIR CONDITIONING & HEAT PUMP SYSTEMS
A/C - HEAT PUMP CONTROLS & SWITCHES
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR FILTER EFFICIENCY
AIR FILTERS, FIBERGLASS PARTICLES
AIR FLOW MEASUREMENT CFM
APPLIANCE EFFICIENCY RATINGS
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BOOKSTORE - Air Conditioning "How To" Books
CAPACITORS for HARD STARTING MOTORS
CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
COMBUSTION GASES & PARTICLE HAZARDS
COMPRESSOR & CONDENSING COIL, A/C
CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS
CONTROLS & SWITCHES, A/C - HEAT PUMP
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
COOLING LOAD REDUCTION by ROOF VENTS
CRITICAL DEFECTS on A/C SYSTEMS
DATA TAGS on AIR CONDITIONERS
DEFINITION of Heating & Cooling Terms
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DUCT SYSTEM & DUCT DEFECTS
DUCTS - Asbestos
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCT SYSTEM NOISES
DUCTS, Asbestos Transite Pipe
DUST, HVAC CONTAMINATION STUDY
DUST SAMPLING PROCEDURE
EDUCATION, HVAC SCHOOLS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRICAL POWER SWITCH FOR HEAT
EVAPORATOR COIL or COOLING COIL
EVAPORATIVE COOLING SYSTEMS
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
FURNACES WARM AIR HEATING SYSTEMS
GAS EXPOSURE EFFECTS, TOXIC
GAS DETECTION INSTRUMENTS
GAUGE, REFRIGERATION PRESSURE TEST
HEAT LOSS (or GAIN) in buildings
HEAT LOSS (or GAIN) INDICATORS
HEAT LOSS R U & K VALUE CALCULATION
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
LOW VOLTAGE TRANSFORMER TEST
MANUALS & PARTS GUIDES - HVAC
MOTOR OVERLOAD RESET SWITCH
MOLD in AIR HANDLERS & DUCT WORK
MOLD INFORMATION CENTER
NOISE AIR CONDITIONER / HEAT PUMP
NOISE / SOUND DIAGNOSIS & CURE
ODORS in AIR HANDLERS & DUCT WORK
OPERATING COST, AIR CONDITIONER
OPERATING DEFECTS, AIR CONDITIONING
OPERATING TEMPERATURES, AIR CONDITIONER
PORTABLE ROOM AIR CONDITIONERS
PRESSURE READINGS, REFRIGERANT
REPAIR GUIDE, AIR CONDITIONERS / HEAT PUMPS
REPAIR & DIAGNOSTIC FAQs for A/C
REFRIGERANTS & PIPING
RETROFIT SIZING for A/C or HEAT PUMPS
SEER RATINGS & OTHER DEFINITIONS
SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS
THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES
WATER COOLED AIR CONDITIONERS
WINDOW / WALL AIR CONDITIONERS
WINDOW / WALL A/C SUPPORTS
Condensate drip trays: this air conditioning repair article discusses the inspection and repair of air conditioning condensate systems, including Air Conditioning Condensate Drip Trays, Defects, and Leaks as part of our review of cooling system condensate piping, traps, drains, condensate pumps, and the detection and hazards of air conditioning system condensate leaks in buildings. A/C or heat pump condensate leak health and safety concerns are also reviewed.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Air Conditioning or Heat Pump Condensate Drip Tray or Condensate Overflow Pan Installation, Inspection, & Diagnosis
A condensate leak or overflow into the drip tray can trip this switch, shutting down your air conditioner or heat pump system.
Frequently Asked Questions (FAQs) about troubleshooting air conditioning & heat pump condensate drip trays & overflow pans
Question: My condensate drain seems clean but the overflow tray still is leaking
My AC unit inside unit overflows into the crawling space. I have cleaned the drain pipe and the air handler coil but the unit still overflows out of the coil tray. What could be the cause(s) of this? - Angel J 6/16/11
Cleaned out the condensate drain pipe with shop vac, bleach, and weak mattress blower.
Only observed draining from the primary pipe during the day (85 - 100 degrees F) but noticed a little dripping from the overflow pipe at night (not continuous). Guessing up to a cup of water from overflow.
Angel: Carson Dunlop Associates' sketch (above left) illustrates what happens when a condensate tray leaks, risking costly damage to the equipment. Your question is why the condensate keeps flowing out of the tray when you are confident that the drain is not blocked.
When the air handler condensate system is leaking into the crawl space and you are sure that the condensate drain pipe is unclogged and properly pitched, I have to guess that there is a problem with the condensate collection pan inside the air handler such as:
There is an almost overwhelming number of products and methods sold for cleaning out A/C condensate lines, drains, and traps, and various tricks of the trade that fit to individual installations and situations. I've used a small flexible bottle brush to clean A/C condensate traps; if the blockage is further along the line I've successfully used a small diameter flexible plastic tube bought at the local hardware store. - DF
Question: A/C condensate leaks into ceiling or into the attic
I noticed leakage in my ceiling after a technician rewired my brand new conditioner to run at a higher fan speed which forced more air into my house. Made sense and now feels cooler. a few hours later is when I noticed the water leak. I went into the attic and can see that there is water in the catch tray but the kicker is that there is a small hole a couple of millimeters round at the end of the tray allowing the water to leak out into the insulation down the roof into my plaster ceiling. What in the world is a hole doing in my catch tray? - Frank 7/22/11
My a/c unit on my roof is leaking into the attic and causing water spots inside the house (ceiling, walls). After having a friend check it out, we think the plastic drip tray, which the condenser is resting in, has a crack or hole causing the leak. The question: How do we get to the drip tray to repair or replace without removing the condenser? - J. 8/1/11
I rent my home and have for 5 years. I noticed a water spot in my bathroom ceiling and went upstairs to check the air conditioner being that it is right above the bathroom. The tray was FILLED. I laid towels down to soak up the water. Today is Saturday. Can I wait to call my landlord on Monday as long as I continue to soak up the water? Also, what could the problem be. It DOES have that switch mentioned above but it must not be working... - Kelli 6/23/12
at higher fan speed sometimes the blower pushes water droplets into the ductwork instead of allowing all of the condensate in the air handler to run into the drip tray. But when you find an obvious leak like a hole in the drip tray, that's a good diagnosis for leaks into the ceiling. If your drip tray is metal it may just have corroded; plastic - it was damaged. Usually there is a primary condensate collection drip pan connected to a drain location, and a separate condensate overflow pan and drain to handle the sort of problem you describe.
replacing the drip tray under a rooftop A/C unit is easy or difficult depending on how it was installed. If the installer left sufficient slack (a flexible loop) in the refrigerant piping and electrical wiring, the system can be raised very carefully, disturbing the piping as little as possible to avoid causing a leak in the refrigerant lines. Then the new tray is placed beneath.
I suspect that the condensate drain is clogged - usually a little brush can clear a trap in that line - but yes, if you keep water from overflowing into the attic by any means you can keep running the system. But it sounds troublesome. I'd focus on getting someone to clear the drain.
Thanks Dan. We will see if the condenser has any slack to lift it off of the tray. Any other ideas?? I also saw someone mention something about some of the moisture from the condenser being sucked into the air intake then resting in the ventilation somewhere, pooling, then leaking. Since the air intake is a big hole just under the condenser, I consider this a possibility. Any ideas on this one? - J
Sometimes in the air handler the blower pushes moisture off of the cooling coil and off into the ductwork - common in very humid spots like Florida.
Question: A/C condensate pan emergency overflow float switch
Can someone tell me what an emergency float switch typically cost? I have one attached to my drip pan on an Amana. - Molly 8/11/11
if you need an air conditioner condensate pan or drip tray float switch installed, the cost will principally be the fee for an HVAC service call to install the switch in the pan (trivial) and wire it to the A/C controls (less than an hour). Figure $100. to $150.
Question: A/C condensate blows into the duct work
An earlier comment mentioned air pushed into the duct by the blower. I have had condensate leaking from the bottom duct of my downflow system for several years on to the garage floor. Has not been a big issue because I live in Oregon and only use AC a few days a summer and humidity is very low. I have determined that the condensate is blowing or splashing out of the tray in the center of the evaporate. The drain is OK. What can be done about this? I will be selling the house next year and I,m sure it will be an issue. - Dan 8/20/11
While some of my associates (M. Cramer, Tampa) point out that a small amount of condensate blow-off at the cooling coil and even small amounts of mold in that area (usually Cladosporium sp. in my tests) are not necessarily a functional issue, I'm still looking for a "fix" for condensate blowing out of the drip tray; I agree that it's common, especially in very humid areas. My associate Mark Cramer, a Florida home inspector and educator, says they just live with it and they don't believe mold is much of an issue in ductwork; I think .... also paraphrasing Mark... it depends. Small amounts of immobile Cladosporium sphaerospermum sticking to insulation may have no detectable effect in the living area; Aspergillus or Penicillium in the same area would be more of a worry. This is a good question to take to the manufacturers to ask what design changes in air handler airflow control may be in the works. - DF
Question: Condensate Drip Tray Replacement
can the drip pan be replaced with out replacing the condenser itself - Peter 5/6/12
Question: Condensate Drip Tray Not Level
Our condensation drip pan is not level, so the condensate water is flowing away from the drain hose and overflowing into our furnace instead of down the drain. I was told the pitch of the pan needs to be adjusted- what is the best and safest way to adjust the pitch? Our AC unit is on top of our furnace. - Tony 6/22/12
Tony, to properly adjust the slope of the condensate drip pan you need to know how it is secured and what movement is possible; I don't have enough information to figure it out from just your comment; you could try sending some sharp photos to the CONTACT US link. If the pan is "pinned" under the A/C unit itself, you may not be able to level the pan without moving the whole assembly. If the pan moves freely it may just be shimmed. But if this is a new problem, that is if it used to drain, I'd look for what changed and ask why - that'd be diagnostic.
Question: Condensate dripping out of the air handler
My indoor ac unit is dripping water from somewhere in the upper part of the system. I checked what I believe is the condensate drain and it doesn't appear blocked. Interestingly, this drain goes into the floor (concrete basement floor) into a hole. I can't see into the hole since it's under a corner of the unit. I cut the PVC drain pipe so I could get my wet vac to it. I didn't get an appreciable amount of junk from the pipe and will replace it shortly. Also, the lines from the outside unit are freezing a bit and I see condensation along the lines that lead to the inside unit. Any information would be appreciated. - Duane 7/8/12
Recently, I have noticed water dripping down the outside of my furnace. The A coil is above the furnace, drain is located on the side of the drip pan, and the coil and integrated pan are "lift able" (not attached to the furnace) so it can be shimmed which I tried. I cleared the drain, but it was not clogged. The drip pan is showing a large amount of rust and I suspect pinholes in it, so the water is dripping through it rather than going to the drain. I have researched and found a product called Pancrete which appears to be made for just this problem. Has anyone here used this product and would they recommend it? System is Ruud upflow furnace approximately 18 years old. - Jeff F. 7/21/12
A first step in diagnosing condensate dripping out of the air handler is to determine if the entry into the condensate drain or any later portion of the drain is clogged - if water can't get from the pan into and down the drain the pan is going to overflow.
Also on occasion I find misaligned A/C components, a pan that is not in the right place, a pan that has corroded and is leaky, or missing insulation on a refrigerant line that is causing condensate to drip somewhere other than into the drip tray.
I haven't looked at PanCrete but will see if I can find and review the product literature; it's worth a try if it can seal a corroded condensate pan instead of having to tear the system apart to get a new one in place.
Question: Blower unit won't come on - the condensate drip tray is filled up - is there a float switch?
my outside unit is working but my blower in the attic is not, After checking my one 10amp fuse I noticed that not only was my drip pans filled but so wa the bottom insulation of my system, I have to separate drain pipe...do I still have a float switch and what should I do next? - Anon 7/16/12
Question: How Much Condensate Flow Should I be Seeing From My Air Conditioner - what's normal?
I have noticed quite alot of water draining from my drain hose which comes from the unit located in the attic. The drain hose comes from the attic unit, then outside and down the side of my home. I placed a bucket under the drain pipe due to the amount of water pooling around the foundation of the home. I can usually fill up this 5 gallon bucket within a day or two with the water draining. Is this normal? - Patrick S 7/30/12
Normal A/C or heat pump condensate flow ranges from nothing to considerable, even quarts per hour in some residential installations and of course still more in larger commercial systems. A system that is operating in a dry environment or that has been on for some time may be encountering little moisture to remove from the conditioned air, while an air conditioner running in very humid conditions may pull an enormous amount of water from the air.
In humid conditions an A/C system can produce a lot of condensate - it's not abnormal unless there is also an abnormal source of moisture in the building. Also when a cooling system is first activated after some period of disuse, as it removes moisture from the building air, more moisture from absorbent building materials (drywall, for example) continues to enter the building air until the moisture level in both air and building contents has been reduced to a stable level.
And of course there is no simple "correct" condensate quantity because in addition to these environmental variables, the cubic feet and type of area being air conditioned varies from building to building as does the dehumidification capacity of the equipment.
you're probably ok.
Watch out: about too little condensate production from an air conditioner or heat pump: we explain in detail at DEHUMIDIFICATION PROBLEMS that if an air conditioner is over-sized it will cool the space off too rapidly and it won't dehumidify adequately.
Questions & answers or comments about air conditioner and heat pump condensate drip trays, overflow pans, and safety switches, controls, and drains
Ask a Question or Enter Search Terms in the InspectApedia search box just below.
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.