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Air conditioner condensate pump FAQs:

Diagnostic questions & answers about condensate pump installation, wiring, drainage, controls, switches, leaks, cleaning. Condensate pump repair, connections, controls, drainage.

A/C condensate pump piping, condensate pump leaks, condensate pump wiring questions.

This article series discusses the inspection of air conditioning condensate pumps & condensate pump control systems, including their proper installation. This is part of our installation, inspection, & troubleshooting guide for condensate piping, traps, drains, condensate pumps, and the detection and hazards of air conditioning system condensate leaks in buildings.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Air Conditioning Condensate Pump Installation & Repair Questions & Answers

Photograph of an A/C condensate pump

These questions & answers were posted originally at CONDENSATE PUMPS - home.

On 2017-08-02 by (mod) requirement for backup condensate handling system


If your existing system has two levels of protection against condenate overflow into the building you may be incompliance with San Antonio HVAC code. Give our local building department a call to describe what you have installed and to ask their opinion.

Cliff Morton Development and Business Services Center Development Services Department Map 1901 South Alamo Street San Antonio, TX 78204

Mailing Address ATTN: Code Enforcement Services P.O. Box 839966 San Antonio, TX 78283-3966 Phone:311

I would not call Mike Shannon, the director, on this as it's really a small matter. But others at the department should be able to help you.

Since San Antonio has adopted the ICC code you can read those condensate disposal guidelines in CONDENSATE PUMPS see

5. Requirements for a Backup Condensate Drain System & Backup Condensate Drain Options

On 2017-08-02 by Robert

I was told by a technician tbat by San Antonio Tx code I need a secondary pan with float switch for my condensate pump in my attic even tho my condensate pump already has a float/safety switch in it. Is this true or is he trying to rip me off?

On 2017-07-27 by chrissy

HI, this may sound like a stupid question but I'm a learning DIY-er. I have a little giant condensate pump (didn't know existed until trying to fix my ac unit). Anyhow, there a two 1 1/2" or so holes on the top, one has the pvc pipe drain going into it, but the other is just open with no cover or anything. I can see the nasty water inside of it, which I'm about to clean out, and seems the valve may be clogged too. Not sure though, bc my unit isn't cooling the condensate pan is bone dry, therefor so is the plastic drain tube...

I trailed off a bit, my main question is does the other hole that has no piping to/from it need to be sealed?

On 2017-07-24 by (mod) temporary disposal of condensate when pump fails


Sure the A/C system will work fine, but condensate isn't being disposed-of. They're independent systems.

I don't like water on the floor: it it wets drywall or other mold-friendly materials you could have a mess to clean-up. If it drains harmlessly to a floor drain you can survive for a time with that knowing that the condensate water may be unsanitary or could harbor unsafe bacteria.

Can you catch condensate in a bucket to pour into a drain?

Can you get to a building supplier like Lowes or Home Depot or a local HVAC supplier? COndensate pumps are simple and not costly. You could even buy one online for next day delivery.

On 2017-07-22 by Kathy

Recently I was cleaning the sludge out of my condense pump when it started to smoke and the it popped! The pump doesn't work now but the a/c still does. Even though water is getting on the floor, is it ok to still run the unit till I replace the pump?

On 2017-07-10 by (mod)

If the lift height is truly unchanged I would look for a kink in the more flexible tubing

On 2017-07-09 by JWD

I installed a new condensate pump and new drain tube to the exterior of the house. When the pump comes on it only pumps the water about 6 ft. high in the tube and then continues to run without pumping the water any further in the tube. The pump works fine when connected to the old drain tube that runs to the sewer pipe (the rise and distance is about the same as the new drain tube to the exterior). The tubing for the new exterior drain is more flexible than the existing tubing. Any ideas? Thanks.

On 2017-05-30 by Eunice

The ac unit is in the basement so I imagine it can be damp to begin with. The only thing I can see looks like condensation. I did notice later there is also condensation on the bottom of the pvc pipe that runs to the pump. The water collecting in the blue pan and the pipe both feel very cold. Crossing my fingers there is no problem and thanks so much for your help.

On 2017-05-30 by (mod) Should there be condensation on the blue pan of the condensation pump?


Perhaps, if condensate is quite cold and the area around the little pumping chamber is both warm and very humid. It doesn't sound like a serious concern as long as condensate is not actually leaking out of the pump.

On 2017-05-29 by Eunice

Should there be condensation on the blue pan of the condensation pump?

On 2017-05-22 by (mod) water dripping out of the bottom of my AC unit

Possibly Samantha, you'll want to take a close look after a few hours;

On 2017-05-20 by Samantha

I change my condensation pump out last night because it stopped working a few weeks ago.

I made sure there are no clogs in the PVC pipe drain that goes into the pump from the AC. The pump works great and is pumping out the water as it fills

There is still water dripping out of the bottom of my AC unit though. Could that be leftover water from when the pump wasn't working?

On 2017-01-14 by (mod) intermittent running of a condensate pump?

I've used Little Giant products on and off for years with good results, but even the best little condensate pumps ultimately need replacement. It sounds to me as if the float switch is corroded, broken, failing. I checked some big suppliers like Grainger and didn't find replacement switch parts - and besides fooling with a switch that can get wet sounds like a risk of death by electrocution.

New condensate pumps like the one you probably have sell for about $50. U.S. - I'd replace it. But FIRST check that the condensate drain line is not crimped or blocked.

On 2017-01-11 by Brian E

I have a little giant condensate pump. It has recently begun over filling and not turning on all the time.

I removed the cover and the float is not stuck and when I manually trigger the switch by usin the float the pump will turn on and run as normal. I noticed some slime buildup and ran some bleach and hot water through it and it will intermittently turn on and off by itself when full.

And other times I have had to manually trigger the switch. I'm not sure what the problem may be and looking for suggestions. Has anyone else experienced a intermittent running of a condensate pump?

On 2016-09-24 1 by (mod) Is it proper to mount the condensate pump inside the return air cabinet space?

The condensate pump can go at almost any convenient location, but it has to be located where it receives drainage from the condensate drip tray or drain by gravity.

For those reasons I don't understand how a condensate pump could be inside the airflow of the air handler - perhaps someone put it in the return air plenum?

Why? Did they power it from the blower motor circuit? Sounds amateur to me; I'd be looking for unsafe wiring too.

On 2016-09-23

by Michael Gonzalez

Is it proper to mount the condensate pump inside the return air cabinet space?

I have come across a system that has the condensate pump sitting on the floor of the cabinet in between the air filter and hvac system where air flows into the heater and passes through the evaporator coil and back through the air duct system throughout the house. It is not outside but inside the stream of air flow. Is acceptable by any means?

Question: Requirement for a trap on condensate drain lines; leaks led to ceiling fan collapse

As a homeowner I installed a condensate pump for my attic-located air conditioner as described above.

When my A/C tech inspected he said a horizontal flow air handler does not have a trap on the condensate output so air is drawn in through the air gap at the pump collection tank.

This air flow keeps the condensate from flowing out the drain until the air handler blower shuts off, creating a tidal wave of water which sloshes where its not supposed to including the emergency drain pan. (My ceiling has fallen in 3 times due to overflowing emergency pan which did not drain properly.) - Bob Farrell 06/09/11



I agree that improperly installed condensate lines that don't drain or a tipped condensate pan that does not slope towards its drain are bound to cause air conditioner or heat pump condensate overflow leaks.

If I understand your comment, you are pointing out that a missing trap on the A/C condensate line can allow air to flow up the condensate line into the air handler, preventing proper condensate drainage and causing leaks and damage to the building.

There is another similar hazard: if an installer routes the condensate line over to a plumbing drain or vent pipe there is a risk that the same effect draws unsanitary or even dangerous sewer gas into the building air ducts

Question: The GFCI Receptacle that powers the condensate pump keeps tripping off - is a GFI required?

Frequent tripping GFI receptacle to condensate pump - Larry B 8/7/11

Does a condensate pump need to have a a GFCI receptacle - Bill Hastings 8/22/11

Reply: how to fix nuisance tripping of a GFCI in a damp area, basement, crawl space, etc.

Larry if the GFCI receptacle powering your condensate pump keeps tripping

- there could be a local short or failure in the pump or wiring

- there could be high moisture in the general area causing the GFCI built into the receptacle to trip - if this is the problem you may be permitted to install a SINGLE RECEPTACLE type electrical outlet dedicated to just the condensate pump, and the GFCI protection otherwise required (recommended too) can be forgiven - you will want to confirm this approach with your local electrical inspector.


Bill, the requirement for a GFCI receptacle for a condensate pump would come from where the electrical receptacle is located. For example electrical codes want GFCI protection in garages and perhaps in basements and crawl areas.

There can be an issue of leak damage if the GFCI is in a damp location and keeps turning off the condensate pump.

In that case you are permitted to install a SINGLE-OUTLET receptacle into which the pump is plugged, and that does not have GFCI protection.

An alternative that I have seen work is to move the GFCI device into a dry location that still protects the condensate pump circuit. See my note to Larry on this topic, just below.

Question: what is the "overflow" box connected to my condensate pump reservoir?

Hi I have a reservoir with a condensate pump in it~ also there is another pvc pipe coming out of the other end of reservoir going up to a box that says overflow. For the first time water came out and on to the floor? any ideas? thanks! Archie 06/02/12


Archie, if that "box that says overflow" is under your A/C or heat pump unit it may be that the main condensate drain line is clogged so condensate is spilling into an overflow pan rather than being routed normally to the condensate pump.

If you've got something else I'd need to see a photo to understand the question.


breaker, fire o matic?, emergency switch all fine, but condensate pump outlet & ac unit will not work - Will 8/1/2012


Will, do you mean that the condensate pump outlet is wired off of air handler circuit or out of a service or utility receptacle that is powered by the air conditioner's own power circuit?

If your A/C system is not running at all start by confirming that it has power and the thermostat is calling for cooling. If the circuit breaker or fuse is on for the A/C circuit but there is no power to the unit, it's time to trace power from the panel thru switch to the unit.

A "fire-o-matic" is an oil line control in my book, so if you're talking about something else, I'd sure like to know about the device you describe by that name- or perhaps send us a photo.

For detailed steps in diagnosing the reason why your air conditioner is not working, start at DIAGNOSTIC GUIDES A/C / HEAT PUMP.

Question: code citation for A/C condensate pump systems

(Aug 2, 2012) Matt said:

I have a primary condensate line going into a condensate pump then pumps into a plumbing vent.

There is no p-trap between the pump and the unit. Is this code? I do understand the gasses could enter through a dry pump (I think that's possible in a dry pump). It is important for me to find out what the code reads as I can't find it anywhere.


An example of code discussing the requirement for a trap in the condensate drain is ICC section 314 on condensate drainage handling

A condensate drain shall be trapped according to the equipment or manufacturers specification.

Question: condensate pump won't shut off

(Aug 5, 2012) charles mc said:

My pump will not shut off. Even though my float is in shut off position, the motor will not turn off !! I cleaned the enter pump and the results are still the same..



It sounds as if your condensate pump switch is bad. The switch on some units is a replaceable part - but if yours isn't, you'll just want to replace the whole unit.

Question: additives for air conditioning or heat pump condensate pump reservoir

(Aug 7, 2012) David Lee Froehle said:

Is there an additive you can put in your condensate reservoir to cut down on the sludge created from the cooling process? It’s plugging up my drain line with a brown slime ( sludge). My furnace and air condition have both been replaced in the last five years.


(Aug 7, 2012) (mod) said:


If the sludge crud is largely comprised of airborne dust (fabric fibers, skin cells) then a additive won't help but good air filtration will.

If the sludge is due to algal growth, the pan needs to be cleaned. I don't see how an additive would help because once added it would just flow out with the condensate.

Question: where to buy repair parts for a Franklin Electric air conditioner condensate pump

(July 13, 2014) Dee said:

I have a VCMA-20ULS condensate pump that works fine. However, the tank itself is cracked and is leaking. Where can I buy just the tank?



The condensate pump you cite is a Little Giant product (Franklin Electric) and is widely sold. But to by just a replacement part most likely you'll need to contact either an HVAC supplier or the company itself.

Question: what to do about condensate remaining in the condensate pump discharge tube

7/30/14 Jim said:

I just installed a new condenser pump n basement, all works fine as far as draining goes.

However, my question is, although the water in the reservoir tank is properly removed, I can see water in the clear removal tube, is that normal? Shouldn't there be no water left in the tube itself after it pumped water out of the unit?


Yeah Jim I too find the water remaining in the condensate tube ugly, sometimes nasty. But it's pretty normal. The pump assembly forms a check valve on the condensate pump end of the tubing so no water should be back-draining from the tubing.

On a separate warning topic, I'd pay attention to crimps and kinks that can block the tubing - and often go unattended until the pump overflows.

(July 31, 2014) Jim said:
THanks ... for the speedy response! However, now another issue ac/furnace unit is literally "dead" no heat or cooling.

I think it's attributed to the installation of the new condensate pump, did I not complete the 24-volt circuit correctly. The thermoastat "clicks" on to start the AC unit to no avail....what should I do? FYI: I checked the fuse; nothing was tripped.


Jim I do want to help but feel like I'm flying a bit blind here. it's likely there are errors or issues we can't "see" by e-text, including possibly unsafe electrical wiring.

Perhaps a wiring error in installing a condensate pump blew a circuit fuse? Certainly normally the power supply and condensate pump operation are totally independent of the electrics of a cooling system or heat pump. The pump operates by the water level in its reservoir.

Check also for a condensate pan switch that might have shut your system down if there was condensate water where it should not be.

Check also for a cooling system door left open - which on the equipment may have opened a door safety interlock switch killing power.

A more organized step by step AC diagnostic procedure begins in the article whose link you'll find by swarching inspectApedia for


Question: metal strap for condensate pump mount?

(Jan 31, 2015) Pete said:
Our condensate pump is wall mounted in the heater/blower cabinet in the middle of the house with a gravity feed inflow and a clear tube outflow to an attic vent pipe.

Unfortunately, the plastic tank spontaneously cracked allowing condensate water to spill for hours into the house causing extensive damage. Could a simple metal strap supporting the pump at the wall have been a prudent prevention? Or should the pump have had another method preventing the damage?



You're asking a fair question but I don't know enough about your installation to have confidence in an answer.

Take a look at whether or not the pump was exposed to vibration or to stress from its existing mounting method. Then compare that with the installation specs for your condensate pump - or give me the brand and model of condensate pump and we can help look for that info.

I mean, a strap holding a pump at a wall - I'm not sure what wall - may sound reasonable but strapping itself could, if tight or depending on where things are mounted - could damage plastic parts such as a pump reservoir.

Question: proper wiring for condensate pump

(Sept 19, 2015) Hugh said:
Just had a gas furnace and air conditioner installed. It uses a condensation pump.

Installer bundled together a shielded electrical cable, two insulated electrical cables (one to the outdoor AC unit, the other to the thermostat), the condensate drain hose (from the AC to the pump) and condensate pump hose.

The bundle is attached to the side wall of the furnace near the front, with cable ties which are screwed into the furnace side wall. The bundled runs right beside an electrical outlet box.

The pump is plugged into this box. The pump sits directly below the electrical outlet box.

Does this sound OK?


I"m not sure that it's all "OK" and I'm frankly two chicken-hearted to pretend I can do an electrical safety inspection of a building's wiring by a brief e-text.

Since new HVACR equipment installation typically requires a permit and building inspections, what do you think about asking for an inspection by your local building department?

Question: selling home, issue with condensate pump drain line

(Feb 16, 2016) Sam said:
We are in the process of selling our house and the house inspection report came up with this "Noted: Recommend condensation drain line from furnace/AC be properly discharged on exterior of dwelling, at time of inspection discharging into sump pit."

The buyers are now asking we discharge it directly outside.

Reply: suete el gallo!

Surely we're talking about a cost of less than $100. I suggest that if that is the only thing your buyers are worried about you should be absolutely elated, and should give them the cost of the "repair" or "improvement" - whichever word is preferable.

The cost, even if you have to buy a condensate pump and 100 feet of piping is still less than $100 for materials or less than $200 for labor and installation - perhaps less than 0.01% of the value of most homes.
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Question: condensate pump mounting, securing, & electrical connections

(June 10, 2016) jodie said:
My condensate pump is not mounted its just lying on floor connected to the tube from the furnace and another line running up across the ceiling into a pvc drain pipe for the sewer. Its plugged into an extension cord which isnt grounded and plugs into the light fixture


Sounds a bit slap-dash; and depending on where you live, a basement receptacle may be required to have GFCI protection;

Question: OK to dump condensate right into the sump pit?

(June 29, 2016) Tony said:
Can I have my upper & lower Indoor AC units drain into sump pump without using overflow condensate pump? And if so how?


Certainly I've seen that done, Tony; the drains are simply routed to the sump pit and typically, in good sump pump design (Search InspectApedia for SUMP PUMP INSTALLATION ) the pit cover will be sealed;

I'd be a bit worried, though, about the possibility of development of bacterial hazards or Legionnaire's disease unless the condensate is being regularly sanitized or regularly pumped completely out - that in turn depends on your climate, humidity, HVAC design, building properties and lots of factors that will set the rate of condensate production.

Question: cascading condensate pumps for backup purposes

(July 1, 2016) Nate said:
I want to run a line from my dehumidifier into one of the unused inlets to my condensate pump, which will severely increase the amount of water staining through the pump. Is there a way to install a backup pump which would be triggered if the primary pump failed?


Sure, Nate. A cascade of pumps with the first one in a bucket so that when it overflows the second one kicks in. I'm not sure I'd bother though; it might be better to simply swap in a higher capacity condensate drain pump and hose.

Question: water on the floor around the central air conditioner drain

(Sept 22, 2016) Rebecca said:
There is a big pool of water outside where my central air drains , what can I do ?


(mod) said:
Find and unclog a blocked condensate drain; search for AIR CONDITIONER CONDENSATE DRAIN to read details. Use the page bottom CONTACT link to send me photos for comment. Keep me posted.

Question: ok to connect condensate to plumbing drain pipe?

(Nov 3, 2016) Kanchan said:

We got one house inspected and we saw that the condensate line is connected to plumbing drain
Is it okay if the condensate line is connected to the plumbing drain vent pipe? We came to know about this in our inspection.


See CONDENSATE DRAIN CONNECTED to VENT PIPE and you'll see there are sewer gas and other hazards.


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