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. Condensate overflow or drip tray leaks, piping, and float switches can shut down an air conditioner or heat pump. These leaks can also damage the building, even causing costly mold contamination. A/C or heat pump condensate leak health and safety concerns are also reviewed.
This article is part of our series of diagnostic & repair articles for cooling system condensate piping, traps, drains, condensate pumps, and the detection and hazards of air conditioning system condensate leaks in buildings.
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As Carson Dunlop Associates' sketch (left) illustrates, one method of insuring against building damage due to a clogged A/C condensate disposal line is the installation of a second, auxiliary drain line to empty the condensate overflow pan that should be installed beneath the indoor cooling unit
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When an air conditioning unit is located in an attic where damage may result from air conditioning system condensate overflow from the primary condensate collection and drain equipment, an additional water-tight corrosion-resistant pan (an air conditioner condensate drip tray or "drip pan") should be installed below the air conditioning equipment to catch overflowing AC condensate should the primary AC condensate drain become clogged.
The sketch illustrates that the condensate drain from the auxiliary condensate tray is not only separated from the primary condensate drain, it is best routed to a different destination and one at which the discharge will be noticed, prompting a repair.
Also, a basement air conditioning system condensate pump can overflow and spill into the living area if the condensate pump fails or if the condensate pump drain line becomes kinked or clogged.
A missing air conditioning system condensate drip tray risks leaks into the attic ceiling, where air conditioner condensate can damage the building or cause a (hidden) mold problem, especially if condensate is leaking onto the upper, hidden (by insulation) attic side of drywall forming a ceiling of a room located below the equipment.
Both the drywall and the insulation itself may become mold reservoirs.
Air conditioning drip pan drains: The air conditioner's condensate overflow pan or tray requires its own separate drain. In the left photo above, the overflow pan has its own drain line, but it joins with the main air conditioner condensate drain line almost immediately.
A blockage in the condensate drain is going to lead leaks out of the air handler into the overflow pan. but since the overflow pan itself shares the same drain the pan will overflow into the building ceiling, inviting a mold problem or other damage.
But this is the most common way we see these drains installed.
Most likely the installer is considering that the main risk of a blockage in the condensate drain system is going to be inside the air handler unit itself. We're not sure what data supports this view.
The float switch approach, discussed next, might be a safer approach.
Float switches on condensate trays: Some air conditioning system air handler installations provide a float switch in the condensate overflow tray. This switch has a floating lever resting in the overflow pan.
The lever senses the presence of water and "floats up" until it shuts down the air conditioning system.
This may be inconvenient in hot weather, but the installer or owner have chosen to protect the building against a potentially costly mold or other leak-related problem by shutting down the air conditioner, forcing attention to the problem.
Remember that if the condensate float tray switch senses condensate in the tray (or is otherwise defective) it will shut the air conditioning system down - if your air conditioning system seems ok but won't turn on, this switch could be one of the items to check. Thanks to Lester Richter for this tip.
Watch out: if your air conditioner has suddenly shut off and won't start, don't forget to check the condensate overflow tray for water, and if this switch was used (instead of a second condensate drain pipe), see if the switch is keeping your air conditioner turned off. If your condensate tray switch is a lever type (shown in our photo) try pushing the lever down to see if the A/C will turn back on. Other switches may have no moving parts: you'll need to remove the condensate and dry the switch.
Details are at CONDENSATE PAN SWITCH LOCKOUT
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 for a service call to install the switch if none is already present.
If there is an drain pan overflow shutoff switch already installed but needing replacement, it should be a simpler operation since it's just a swap-in part. The wiring to the HVAC system controls will already be in place.
The condensate pan or overflow pan safety switch itself, such as the Safe-T-Switch Model SS3 made by Rectorseal and sold as a drip pan overflow shut-off switch, retails from $30.00 to $50.00 U.S. 
Don't forget to find and fix the cause of condensate leakage into the overflow tray or you'll continue to have air conditioner operating problems.
Since normally condensate produced in the indoor air handler is carried from the air handler interior to a condensate drain, we don't expect to see condensate falling into the condensate overflow drip tray as a normal event.
If we see evidence of leaks into the condensate tray, the air conditioning system service technician should investigate the cause of this condition.
Readers who need to clean or unclog a blocked or leaky overflowing A/C or heat pump condensate drain should
see CONDENSATE DRAIN CLEAN & DE-CLOG.
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.
Primary condensate pipe still clogged? What kind of plastic tube would work as snake? - Mark 6/27/11
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:
- the drain in the pan itself is clogged with debris - you'll need to turn off and look inside the air handler
- the drain pan is corroded through and leaks - it will need patching or replacement;
- the drain pan or the whole air handler is not properly leveled - it may be sloped away from the condensate pan drain opening so that condensate collects in and runs over the edge of the pan in another direction.
Let us know what you find - it'll help other readers.
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
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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.
But if there is insufficient slack in refrigerant tubing and wiring, moving the system to install a new drip tray is a big deal because you'd have to evacuate the system, cut refrigerant lines, then install the tray, then repair the lines and clear and recharge the whole system.
That procedure is so much trouble and cost that most folks will try to find and repair leaks in the existing drip tray first.
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.
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.
The switch itself, such as the Safe-T-Switch Model SS3 sold as a drip pan overflow shut-off switch, retails from $30.00 to $50.00 U.S.
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
can the drip pan be replaced with out replacing the condenser itself - Peter 5/6/12
Yes, well sort-of. It can be difficult on many air handlers to get a new drip pan in place inside of an air handler without doing some disassembly. But drip pans and their replacement take place inside the indoor unit, the air handler or blower unit - and have nothing to do with the outdoor condenser unit.
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.
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.
Condensate drip tray replacement under an A coil in a cooling system such as the one you describe can be tight.
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
Float switches are used in condensate OVERFLOW pans as a safety measure to shut down the system when condensate is not draining properly - to avoid a flood out of the pan and into the house ceilings. But if your overflow pan has its own drain it usually won't have an overflow switch. In other words usually there is either an overflow pan with a drain, or an overflow pan with a water-sensing switch that shuts down the system if ANY water appears in the overflow pan.
Because you say your overflow pan has a separate drain pipe, I suspect it won't have a switch.
If you had an overflow switch you would see it and its wires somewhere in the bottom of the overflow pan.
So you need to look for a different problem: lost power, a blower compartment door open (those have a safety switch that shuts off power if someone opens the door - to avoid getting chopped by the blower fan), or a bad control, relay, etc.
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.
As long as
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.
(June 23, 2014) jv said:
my outside unit turns on. I checked the drain pipe and put bleach and tried to flush with water still the blower inside the unit doesn't turn on. I changed the air filter, checked the power, changed the batteries in the thermostat as part of figuring out the problem. If I turn the air conditioner on then it starts to show condensation on the panel of the furnace and it feels really cold but still no blower. I don't see the drip pan and I don't know what the overflow sensor would look like for me to check these before I call for service. I have an American Standard Freedom 80 unit in my hall closet. It is 6 years old. If I call an air company what would they typically charge for running diagnostics, and replacing a blower or blower motor or drip pan/sensor? Just trying not to get scammed. Thank you
JV it sounds as if your blower fan motor is not running. A condensate pan overflow switch could indeed leave the blower OFF, as would a blower compartment door switch if the door was not fully shut - you'd want to check these simple conditions before paying for a service call.
If those steps don't help and given what you've already checked, I suspect there could be a broken fan belt if your blower uses a fan, or a blower motor that's not working, or a bad fan relay or control. Typically the service company charges a minimum fee for a service call + parts. Under $200. The tech will check for power at the fan, check the fan motor and controls, etc.
(July 2, 2014) Brenna said:
My brand new attic ac unit is dripping quite frequently in a few places directly undeath the unit itself. I've also noticed that the area around my drip pan is saturated but the water level inside the pan isn't very high at all. First of all, should there be dripping of this nature directly from the unit and not from a drainage tube, duct work, etc and what is causing the saturation around the perimeter of my drip pan with such low water levels inside it? Could my pan (approx 5 weeks old) have a crack?
Brenna, check for a clogged or misrouted condensate drain, a unit that is not properly sloped to send condensate into the drain, or missing insulation causing condensate to form sand drip in a spot where it misses the drip tray
(July 14, 2014) Rebecca said:
Our AC will not turn on. The fan will not turn on either. I am trying to figure out how the overflow safety switch feature works and how to fix the tubing in case it is clogged. I was able to pour the water out of the condensate tray but it is still not coming on. Is the safety switch inside the pump? I cannot find the switch. The pump did start when I was tilting it to pour it out. But the AC is still not kicking on. MODEL kt3x-2ul automatic condensate removal pump
Rebecca, not all condensate pans use an overflow switch - some provide dual condensate drains at different levels, or a second pan below the first one.
If there were a condensate pan overflow switch you'd see the switch and wires leading to it right in the condensate tray.
Aug 10, 2014) Tamieka said:
I have a Goodman Heat Pump & Air Conditioner Model a36-10 serial number 9506121001. The air blowing from the vent was very faint. I had to put my hand all the way up to the vent in order to feel the air. I replaced the blower fan...that didn't help. The drain line was clogged...got that cleared. The main culprit appears to be that the safety switch wasn't working and when it was repaired the air blew out really hard. I was told that the safety switch caused the outside unit not to run, only the attic unit had been running. I am no in search of the safety switch to replace the part bc it continues to go out. Is there a universal switch...a switch specifically made for the drain pan...or a switch specifically made for the unit brand and model? I had someone to take a pic of it so I'd at least recognize it if I see it but I haven't had any luck yet. Please help! Thanks in advance!
Thanks for the interesting question, though if this helps I have to say I can't make sense out of what you were told.
If an outside compressor is not running the result is that refrigerant is not sent to the indoor cooling coil in the air handler - so air won't be cooled.
But the outside compressor has no direct effect on the fan speed of the indoor compressor condenser unit.
I'd think that if there were a safety circuit that shut off the air conditioning system on sensing that the compressor was not working at all, there would be NO air flow, rather than weak air flow.
I'd like to know what safety switch we're discussing. For example a door safety switch turns off the indoor air handler if one if its opening covers is ajar.
(Sept 5, 2014) Van said:
Hi, we have the overflow switch installed but the drain pan cracked twice within the last 4 years. The installer said due to the cracked drain pan, it did not hit the overflow switch. As a result, water leaked into bedroom and bathroom. Should there be secondary pan when the drain pan & overflow switch fail? Who should handle the cost to replace drywall, carpet, etc?
The pan you describe already was supposed to be a backup to the primary drain system. I would not add a third one. Rather, fis the reason for pan cracking and fis the primary condensate drain that should not be leaking into the overflow pan in the first place.
(Sept 23, 2014) Anonymous said:
If I have an AC line inside a pitch pan and it is broke, how does the roofer/AC guy make repairs to this line since the pitch pan is full of some type of sealant?
(Sept 24, 2014) Rob said:
My Ac and heat both aren't working all of the sudden the fan blows but it seems to be just circulating air not heating or cooling it.
Rob in the article links at page left, the diagnostic suggestions at
LOST COOLING CAPACITY
should help you
(Oct 3, 2014) Joe G said:
My Ac does not have a secondary/ overflow pan. I was considering having one installed but not sure how much is reasonable. Any idea what's the going price?
The install price for a drip pan depends on the trouble of getting it in place - the pan itself is a trivial expense - along with the trouble of routing its discharge piping to a suitable drain location. So I don't know what your case involves.
A much less costly alternative that is fine for many buildings is to install a condensate overflow switch that will shut off the system if the primary pan is not working properly - say clogs and doesn't drain.
(Mar 20, 2015) Anonymous said:
Are coil drip pans and backup exterior base pans always metal or can they be plastic? In either case can either crack or develop holes and leak?
Yes to all of the questions
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