Air conditioner, heat pump & condensing boiler or furnace condensate handling & drainage defects:

This air conditioning repair article discusses the inspection, diagnosis, and repair of air conditioning condensate drainage systems, including condensate leaks, condensate piping, traps, drains, condensate pumps, and the detection and hazards of air conditioning, heat pump, or condensing boiler or furnace condensate piping, drains, & condensate leaks in buildings. Condensate leak water health and safety concerns are also reviewed.

This document describes the inspection and repair of condensate handling systems for residential air conditioning systems (A/C systems) to inform home buyers, owners, and home inspectors of common cooling system defects.

Condensate Handling: Air Conditioning / Heat Pump Condensate Handling Defects

These questions and answers about proper handling of air conditioner or heat pump condensate disposal were posted originally at CONDENSATE HANDLING, HVAC - topic home. You'll want to review that article.

On 2018-10-01 by (mod) - Will multiple package units hook up on the same Condensation pipe Pass inspection

OM

Man I wish I could promise what a local code inspector will do. I can't, and she's the final legal authority on code compliance.

But in general, IF the piping capacity is sufficient and there are no missing traps I'd figure the inspector will be ok with that.

On 2018-10-01 by O.M.

Will multiple package units hook up on the same Condensation pipe Pass inspection

On 2018-05-16 by (mod) - PVC drain lines are glued, not taped together.

Confused:

PVC drain lines are glued, not taped together. If you see a PVC drain put together with some kind of tape I suspect it's an amateur job.

On 2018-05-16 by (mod) -

I have seen that done and it might work in a non-freezing climate, but, then, where is the downspout dumping the water?

On 2018-05-16 by Melvin sickels

Can you run a roof a.c. condensation drain line into a roof gutter

On 2018-05-16 02:59:47.252649 by Melvin sickels

.can you run the a.c. drain line into the roof gutter

On 2017-11-16 20:13:00.112219 by Confused

Should a company use tape to secure a condensation drain line instead of gluing it? If it had to be taped does that mean that they were trying to get a new system and old lines to fit?

On 2017-07-21 17:06:18.107071 by (mod) -

Tomar

A new coil installed in an existing system? Did the tech replace the condensate drip tray?

In any event it makes sense to open the system and take a look.

Sure I agree that condensate may not run where it should if a pan is tipped or the piping is improperly routed or clogged.

On 2017-07-18 22:26:58.156616 by tomar

Thanks for your reply. This is a new evap coil so I doubt if there would be a leak in air handler or in condensate pan inside the plenum.

Could it be that the plenum/evap-coil is not leveled correctly leading to water due to condensation coming down both primary drain pipe (opens outside the house) and the secondary drain pipe (opens into a drain pan)?

On 2017-07-18 13:39:24.582775 by (mod) -

Check for leaks from the primary condensate pan or air handler into the overflow pan.

On 2017-07-17 20:38:47.164864 by tomar

I have a situation where the main drain line looks fine (unclogged) because I see water dripping from it however I still see the secondary drain line (that opens into drain pan) leaking 4-5 drops every minute. This is getting collected in drain pan which eventually drains it outdoors. Is this normal in high humidity time of the year (July in NC) ? This was a replacement installation (only evap coil replacement) done last year. Could this be an incorrect/unbalanced installation issue?

Thanks

On 2017-04-08 19:17:44.808446 by (mod) -

George

Often an installer includes both a main condensate drain and a backup or overflow drain pan with a separate drain to catch any leakage should the primary system fail for any reason - that's a good design in my view.

On 2017-04-08 02:49:19.674247 by george

fan coil unit drain pan has two condensation pipes

On 2017-01-14 18:19:38.103441 by (mod) -

I am really confused by this question, Dhinesh.

It is common to trap each condensate drain at each pan but it would most-likely be perfectly functional to drain multiple pans into a common larger drain and to do the trapping there.

On 2017-01-14 04:28:37.803958 by Dhineshbabu

if an ACU provided with a drain pan, which got splits to three sections (ex- two beneath the coil & another beneath the compressor) only there plates were provided to separate it upto pan height, separate drains were taken frm these sections ( 3 drains). whether i could connect these three drains to one trap,or i could go for three individual traps. if not one trap what is the reason?

On 2017-01-14 by (mod) - common to trap each condensate drain at each pan

I am really confused by this question, Dhinesh.

It is common to trap each condensate drain at each pan but it would most-likely be perfectly functional to drain multiple pans into a common larger drain and to do the trapping there.

On 2017-01-14 04:28:37.803958 by Dhineshbabu

if an ACU provided with a drain pan, which got splits to three sections (ex- two beneath the coil & another beneath the compressor) only there plates were provided to separate it upto pan height, separate drains were taken frm these sections ( 3 drains). whether i could connect these three drains to one trap,or i could go for three individual traps. if not one trap what is the reason?

On 2016-12-18 14:45:02.372850 by Anonymous

Is it within code to run a drain from a closet model upflow air handler to a floor drain inside the R/A with a trap before the floor drain and tied in with a coupling and a 2x3/4 bushing

On 2016-10-15 00:49:43.504393 by Condensate drain pan air leakage

There's a massive amount of air leakage around my air handler's drain pan. I can't imagine this is intended (is it?), Since it almost looks like whoever installed it didn't even bother lining it up properly.

How do I line the pan up with the handler? The air handler seems too heavy to lift on my own... and ya know, everything is connected.

On 2016-09-25 14:45:14.292045 by Tony

How long can I extend my drain line pipe from outside my house

On 2016-09-25 14:44:38.511496 by Anonymous

How long can I extend my drain line pipe outside the house

On 2016-08-05 23:56:49.370598 by Anonymous

What size pipe

On 2015-11-17 02:04:57.204717 by (mod)

Pete:

I'd be looking for an indoor moisture source or looking at a change in the "on" cycle or fan speed of the unit.

On 2015-09-28 01:44:52.136767 by Pete of Tustin

Hi. Thanks for having such an informative website. I have a heat pump that seems to have some crazy amount of condensation this year in cooling mode.

The eval portion of the unit is beneath the house and is below the city drain lines by about 6 feet. Although I never did initially measure the air temp at the air outputs, It seems as if the air is not blowing out as cold as it once did years ago.

It is my understanding that refrigerant is an excellent escape artist. I never needed a pump before but now it seems as if the trap is not enough and the condensate does not evaporate fast enough like it once did. Is it possible that I could be getting higher condensation and higher air output temperatures due to a reduced amount of refrigerant in the system? I don’t think I have a leak but I have not had the unit pressure checked, or rather any refrigerant added in over 5 years.

Could my new condensation abundance be due to a reduced amount of refrigerant along with reduced output temperatures? I do not have any frosting problems. Thanks in advance for your help.

On 2015-08-14 16:41:35.268385 by (mod)

Bleach is not really a drain de-clogging chemical, though it might help cut some greases.

If your A/C is not turning on, check for a condensate overflow pan safety switch.

If your A/C turns on but does not run properly I suspect bad wiring, bad control board, low voltage, or a motor obstruction. Leave the system off pending repair as trying to run it in that mode may cause further damage and could also risk a fire or shock.

On 2015-08-14 01:06:42.490051 by Anonymous

My drain was clogged so I did the usual and poured some bleach into it, nothing budged so I pulled the hose from the pipe, got the clog out and put it back together. Turned ac back on but it doesn't seem to be fully turning on like it should be, just barely blowing any air.

Then I noticed that bleach water is dripping from the center part and front of the indoor part of the unit. Outside unit running fine. Could the drain have backed up into the unit? Please tell me that isn't what happened and how to fix this!?!? KD

On 2015-07-17 19:54:17.432948 by (mod)

Chris look for a running toilet that's keeping the drain lines cold with drainage.

On 2015-07-11 10:47:48.861580 by Chris

I have lived in my home for over 4 years and suddenly I have condensation on drain lines coming from my upstairs to the downstairs/main line exit pipe. I also found condensation on the ac drain line which is connected to the bathroom sink upstairs.

The upstairs is not used much and the only water running through the drain is from the ac unit in the attic. I'm assuming I am now seeing condensation after 4 years because there has been an increase in cold water running through the drain pipes or an increase in cold air running through the drain pipes.

What would cause an increase in the water running from the ac unit? (knock on wood to prevent jinx) AC has been cooling home fine.

On 2015-04-23 17:21:03.018700 by (mod)

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies

Question: Our heat pump spills water onto the floor. What's wrong and how do we fix it?

I have a question regarding our heat pump. Last summer it started leaking water. The system otherwise runs fine but we have to keep a bucket where the water comes out a rubber tube. This also does not catch all the water because the carpet still gets wet. There is no problem with heating this past winter. Is there a pump of some kind that needs to be replaced.- M.M.

Reply:

It sure sounds as if your heat pump when in cooling mode is leaking condensate into the building. When warm moist indoor air passes through the cooling coil, moisture is removed from the air as it cools, condensing into water that must be drained away to an acceptable location - a floor drain or in some areas outdoors onto the ground.

A condensate leak that spills into the building interior could be caused by any of several problems such as a clogged condensate drain line or if a condensate pump is used to lift condensate from a receiving container up to a building drain, the pump could be switched off or broken.

You need to first diagnose the cause of the problem. If it's just a clogged drain line, clearing the line can get things working again quickly and probably at little or no cost. If you are unfamiliar with the equipment or can't find the condensate handling system, or if a condensate pump is not working you probably need a service call by an HVAC expert.

Look through the articles found in the links listed at the ARTICLE INDEX the bottom of this article under CONDENSATE HANDLING for more details about different condensate handling problems, diagnoses, and repairs.

Watch out: in a good heat pump/air conditioner installation, the installers make provision to protect the building interior from condensate leakage should the primary condensate drainage system fail. Usually that's in the form of a condensate drip tray that is placed under the indoor air handler where the cooling coil is located (and where condensate is produced).

If the condensate drain system fails and condensate begins to leak out of the equipment, the drip tray either takes condensate safely away to a drain by a separate drain line or it uses a switch that shuts down the equipment so that you know repairs are needed.

Condensate that leaks into building carpets, ceilings, walls, risks formation of a costly mold contamination issue. So get this matter repaired promptly.

Question: Water blowing down my HVAC Supply Ducts, What Can I Do to Stop It?

Why is water blowing down my supply duct system? I have solved the freezing up problem, I don't have a drain problem!! I added refrigerant to solve the freezing up problem, but it is still blowing water down my supply line. How do I stop this?? - C.T.

Reply: Check the A/C system sizing, check for abnormal indoor humidity sources

If you are sure that the condensate drain is in fact draining, I don't know a simple in-air-handler fix for this problem - it's common in some humid areas such as Florida. I'd take a look at these next steps:

1. Check whether or not your A/C system is oversized for the space being cooled; a cooling system that is oversized will not dehumidify adequately and that leaves too much water in your building air
2. If #1 is not the issue, look for and fix sources of abnormal indoor moisture: leaks, failure to use bath and kitchen vent fans, particular lifestyle that puts lots of moisture into the air (cooking?); and consider some auxiliary dehumidification

Question:

(May 3, 2014) Anonymous said:
I have split a/c the problem is water drain from indoor unit

Reply:

Find and fix the clogged condensate drain or leaky condensate drain pan

Question:

(June 4, 2014) Ekim said:
major water condensation in blower unit in attic, secondary pan is doing the draining at this point, blower unit pan seems to be rusted, and water does not flow to over flow pipe (rheem unit abou 12 years old) any idea or product to seal the pan and get the water to flow to the pipe, the outside pan is saving the day now but need to fix this issue. is there enough room under the coils to put a platic of some sort? will the plastic start to mold?

Reply:

Sounds like the primary drain pan needs replacement; check first for a clogged condensate drain;

Usually you won't have space to add an additional drip pan below the coils but may have room below the whole unit; the problem is that the leaks in the existing pan may be sending water where it causes other damage.

Question:

(Jan 29, 2015) Anonymous said:
What can I put a salt tablet in the condensate pump to keep condensate drain line from freezing when out side temperature drops very low.

Reply:

Sounds doubtful; if condensate is passing through the drain the salt won't remain nor would other antifreeze. Try a heat tape if you can't protect the line from freezing.

On 2012-08-16 14:27:28.137935 by Will

I have 2 HVAC units that are less than a year old. The condensation tube on one of the units has become extremely discolored (a light yellow color) throughout the majority of the tube. The tube on the other unit is still perfectly clear. Is this common? Should I be concerned?

On 2012-07-23 23:49:38.353720 by (mod) -

Merritt,

It sounds as if your condensate drain or trap is / are clogged. Try cleaning the trip first.

Norma, some condensate blow by at the cooling coil is common in very humid weather, but leaking into the building or pooling on the floor outside the unit is clearly a problem. I'd start by checking to see what's wrong with the condensate drip tray and drain.

On 2012-07-23 23:27:19.073419 by Norma

My blower is sucking the condensation through the coils and it's puddling at bottom of my unit and water getting into the floor in my hall way.

On 2012-07-21 05:31:48.652783 by merritt

Our heat pump has condensate pooling below the unit. It has a PVC drain pipe installed running to a floor drain but I have some questions about the way it is routed. It has a "trap" (for lack of a better term) in it as shown in the 4th photo on this page. Is this correct and if so, why? It seems to me water could never drain past this. It also is routed on the level floor around three sides of the unit instead of taking the direct route to the drain. Again, is this correct, and why? Our unit does not have a condensation pump. Can I just clean out this pipe and reroute it straight to the drain w/o the up and down 90 elbows? BTW, we had a HVAC guy here and said it was working OK.

On 2012-06-05 19:21:09.901267 by (mod) -

Florida,

I suggest inspecting the interior of the air handler unit to see just what is rusting - you might catch a condensate leak problem or other damage before the unit rusts- through and thus avoid leak damage to your building.

On 2012-06-05 17:12:26.653686 by Florida dude..

Is it normal to see a rust inside the drainage pipe coming from the evap coil?? My unit has a safety feature to stop the a/c unit if the drainage over flows and does not drain. I decided to pull the piping around the air handler to clean it better an noticed rusty water...But I also hand the evap coil replace last year..

On 2012-05-29 16:32:20.079230 by (mod) -

Gene, condensate production slows once the in-building air has been dehumidified when an A/C has been on for some time. If no condensate is ever produced you'd check for a blockage or leak in the condensate drain system.

On 2012-05-27 14:34:24.020154 by Gene O

I am not seeing any water draining from my Central Air unit when the A/C is running.

It seems to be cooling but I haven't seen any drainage. Does this mean the condenser isn't working or do I just need to wait until the A/C has been on for a while?

On 2012-05-12 13:19:38.594292 by Cyndy Black

Can the evaporator coil be "fixed" or when it's shot, it's gone completely? Also, the pipe that leads from my outside a/c unit and goes into our furnace is leaking right at the joint. A small puddle of water is under the furnace.

The a/c guy inspected everything: no freon leaks, no freezing up, pans and hoses are clear, etc. He said to tape and wrap that joint real good and see what happens. If it still leaks, the evap. coil will have to be replaced. Is this correct? Thank you.

On 2012-03-29 20:11:38.496118 by John T.

Sorry, I meant the coil in the air handler where the air returns (evaporator?). I took out the blower fan and the blades are rusty as well as the mount for the motor.

The inside of the handler, made of that "furry" material, has plenty of mold also. Can I replace that material or do I need a whole new box or cabinet or whatever it's called--the thing that everything is encased in?

On 2012-03-28 22:04:36.599916 by Anonymous

John, I'm not sure what an "intake coil" is - perhaps you mean a cooling or evaporator coil in the air handler?

In any case, I think the immediate steps are:

- clean the coil
- install or make sure you have effective air filtration upstream from the coil, preferably at the return air inlet register(s)
- inspect the ductwork for damage or dirt or debris - depending on the duct material (metal, for example) it can be cleaned.

Let me know what you find and perhaps send along some photos (see the CONTACT US link at page top or bottom) - we may be able to suggest more steps.

On 2012-03-28 21:04:28.865782 by John T.

I am battling a wet intake coil. Our house is very dusty and between the dampness of the coils and the errant dust that manages to get into the coils, I seems to clog up the coils. Where do I start???

On 2011-09-27 22:01:39.435525 by Ala3n (aka Anonymous)

Thank you Mr. Friedman. Of course you are right that I was referring to the wrong piping. You managed to answer my real question even though I was not able to ask it. Much appreciated. Pax, Ala3n

On 2011-09-27 21:49:28.496714 by (mod) -

Anon, the condensate line only carries condensate (water) and perhaps debris and dust from the system.

It might need cleaning or if in poor aha EM replacement. But it never carries freon. If you actually mean to be discussing refrigerant piping, perhaps you refer to piping between the compressor and he air handler, usually those pipes are reused.

Cleaning includes pulling a vacuum on the system before charging with refrigerant, and perhaps installing one or more refrigerant filter dryer units.

On 2011-09-27 21:44:43.698070 by (mod) -

Ben, thanks for the nice note, we are so happy when our information is useful, and don't hesitate to ask if any of our articlesn are unclea or incomplete.

On 2011-09-27 17:26:31.542397 by Anonymous

Getting estimates for replacing my 21-year-old A/C and furnace, I got conflicting opinions regarding the condensate line. One installer said the existing line could be blown out using a chemical but another said I should replace the pipe with a new one because the freon residue would cause problems with the new puron discharge. Is this $300 or so condensate line replacement necessary? Ala3n

On 2011-09-27 11:45:33.778387 by Ben D.

The overflow pan below my system kept filling up and the float switch tripped the system off. Your descriptions of the potential problem led me to inspect the condensate drain line via a removeable cap and I found the trap to be clogged. Saved alot of time, effort and a service call. Thanks

On 2011-09-07 18:59:04.091050 by (mod) -

Steve the drain may be leaking, or it may be chilled itself, causing condensation on the condensate drain piping. Look closely at the air handler and drip pan for leaks.

On 2011-09-07 16:01:24.993589 by Steve Sklavos

My air handler is under the house in a crawl space and the condensate line seems to be draining just fine, but I have moisture on the drain line and a puddle of water under the unit. Any idea what could be causing this? Thank You

On 2011-09-04 02:04:45.871679 by (mod) -

A standard condensate pump available from any plumbing or HVAC supplier should have the lift capacity you need JM.

and under CONDENSATE DRAINS (links in our ARTICLE INDEX) you'll see "Locations for Condensate Disposal" and additional articles that explain where to dump the condensate water and where not to send it.

On 2011-09-03 18:57:41.698361 by JM

Need to route condensate up to 9.8' from the ground. from a mini split installed 7 feet from the ground. The water will need to travel 30 feet to the outside wall and arrive at the end 9.4' off the ground.

It will then drop 8' and exit through a small hole to the outside and then exit the hose 2' away from building. What type of pump do I need to install behind the inside unit to make this installation perfect? Is there a better way to do this?

I have a bathroom 10' away where I can route the condensate on a 10 degree slope. Where in the bathroom should I dump the water?

On 2011-07-20 18:00:12.556440 by (mod) -

Allan, I don't think a clogged condensate drain would cause freezing. More likely reduced air flow over the coil or low refrigerant would be at fault. If the low refrigerant level continued to drop due to a refrigerant leak, ultimately you'd have no cooling.

On 2011-07-20 15:47:44.358506 by ALLAN GLAVAN

I have a home in central Florida that is approximately 800 sq. ft. total. It has a 3 Ton air conditioner. Up to this summer, it worked fine. But now the evaporating coil freezes over with ice. I am somewhat concerned that the condensate drain system may bve some of the cause of the freeze up although I did clean out the drain from the pan.

I then turned off the system for two days to allow the coil to thaw and started it up again. Ir appears that little cooling took place and the system apparently froze over again.

The air circulation was great--I replaced the single air filter but after a short while I wasn't able to pull any temperature down.

What is the best solution to this problem outside of buying a new airconditioner? The temps and humidity are usually high during the summer months and it seemed to work well before.

On 2011-07-11 by (mod) - difference between main and backup condensate drain systems

Merlin:

Main Condensate drain:

In a good A/C installation the condensate produced at the indoor handler is collected inside the unit and routed to a condensate disposal system - a drain or a condensate pump that pumps to a drain. That condensate drain or pump will have its own individual drain piping to dispose of condensate in normal use.

Backup condensate drain:

in a good A/C installation, a backup system is provided to catch condensate overflow if the first drain pan or drain line leaks or becomes clogged.

We use a second, independent drain on the backup system precisely because a common condensate disposal problem is that the primary condensate drain line becomes clogged with dust and crud.

If the backup condensate overflow pan simply connects to the primary condensate drain pipe there is a good chance it won't work when needed.

Single-Drain Condensate Handling:

An alternative installation uses a float switch in the condensate overflow pan rather than a drain pipe. In this installation you'll see only ONE condensate drain pipe.

If the primary condensate drain system fails and condensate begins to collect in the overflow condensate pan the float switch senses the water and turns off the system.

On 2011-07-10 00:52:47.806780 by Merlin

Why are there two drain lines and only one hooked up to the sump pump?

On 2011-05-31 16:27:19.521729 by (mod) -

When you don't see condensate coming out of the condensate drain pipe there are several possible explanations:

- there could be a clog in the drain system - look inside for condensate leaks, overflow, or perhaps the backup condensate drain is handling the problem, in which case you need to fix the primary condensate drain

- humidity in your area could just be low and you're not producing condensate

An air conditioner blower that runs continuously

- could be due to the "fan on" switch being set at your thermostat
- could be due to the room thermostat never being satisfied - you've lost cooling capacity -see our link in our ARTICLE INDEX titled LOST COOLING CAPACITY

On 2011-05-31 16:18:08.550154 by dan

there is no condensate coming out of the outside pipe and the blower continuisly runs

...

Continue reading at CONDENSATE HANDLING, HVAC - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

HVAC Condensate Articles

• CONDENSATE HANDLING, HVAC
  • CONDENSATE LEAKS
  • CONDENSATE PUMPS
  • CONDENSATE DISPOSAL, IMPROPER
  • CONDENSATE DRAINS, CODES
  • CONDENSATE DRAIN CLEAN & DE-CLOG
  • CONDENSATE DRAIN INSULATION REQUIREMENTS
  • CONDENSATE DRAIN PROBLEMS
  • CONDENSATE DRIP TRAY DEFECTS
  • CONDENSATE PAN SWITCH LOCKOUT
  • Legionella BACTERIA & HVAC EQUIPMENT
  • CONDENSING BOILER/FURNACE CONDENSATE DRAIN
  • HARTFORD LOOP
  • Legionella BACTERIA & HVAC EQUIPMENT
  • SPLIT SYSTEM AC CONDENSATE LEAK REPAIR
• CONDENSING BOILER/FURNACE CONDENSATE DRAIN
• DUCT SYSTEM DESIGN SIZE & DEFECTS - home
• SLAB DUCTWORK
• WATER & ICE IN DUCT WORK
• WET CORRODED DUCT WORK

Suggested citation for this web page

CONDENSATE HANDLING FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

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