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.

Air Conditioning Condensate Pump Installation & Repair Questions & Answers

These questions & answers were posted originally at CONDENSATE PUMPS - home. Be sure to see the condensate pump installation, inspection, & troubleshooting help given there.

On 2022-09-02 by InspectApedia-911 (mod) - Can you feed one condensate pump line into another condensate pump?

@Bobby,

The downstream condensate pump has to have the pumping capacity in rate or gpm AND the piping diameter, to support the total combined condensate volume that will arrive in the pump's reservoir.

On 2022-08-30 by Bobby

Can you feed one condensate pump line into another condensate pump? If so, are there any requirements on the size of each pump (i.e. does one pump have to be bigger than the other)?

On 2022-08-15 by InspectApedia-911 (mod) - Aspen mini-lime condensate pump wiring guide

@John,

See this

ASPEN MINI-LIME CONDENSATE PUMP WIRING GUIDE [PDF]

https://inspectapedia.com/aircond/Aspen-Mini-and-Maxi-Lime-Wiring.pdf

FYI there's also this ASPEN MINI-LIME PUMP DATA SHEET [PDF]

https://inspectapedia.com/aircond/Aspen-Mini-Lime-Data-Sheet.pdf

On 2022-08-15 by InspectApedia-911 (mod) - check the condensate pump installation against the wiring instructions in its manual

@John,

The safe way to answer this question is to check the wiring diagram in the instructions for your specific condensate pump brand and model.

Examples - that might not be your pump -

BDP MITSI MANUAL BLUE DIAMOND CONDENSATE PUMP MANUAL [PDF]
inspectapedia.com/aircond/Blue-Diamond-Condensate-Pump-Instructions.pdf

MITSUBISHI ELECTRIC Air Conditioning For Building Application Drain Water Lift-Up Kit PAC-KE05DM-F
Installation Manual [PDF]
inspectapedia.com/aircond/Mitsubishi-AC-Drain-Lift-Pump-Manual.pdf

MITSUBISHI CONDENSATE DRAIN PUMP IO MANUAL [PDF] Model PAC-SH94DM-E PKA-RP.KAL PKFY-P.VKM-E
inspectapedia.com/aircond/Mitsubishi-Condensate-Pump-Manual.pdf

On 2022-08-15 by John

Hello, I need help with a aspen mini lime condenser pump. There’s two sets of wires on it. One’s hooked in already.

The other has a gray,purple and orange wire. Unit is Mitsubishi and has three spots to connect to (S1 S2 S3) (4th if You count ground).

I need to know where these wires go into.. read and been told by company the orange wire remains capped and does nothing. So purple and gray, where is their home. The other set of wires has a black going into S1 and the green going to ground and the red going into S2 so these are already in place.

Just need to know about the red and the black please. Thanks.

On 2022-05-20 by Friedmandaniel911 (mod) - condensate pump appears to be draining into itself

@J Burrows,

You're absolutely-right J.B.

As we show in an annotated copy of your photo (below), condensate draining from your HVAC system into the condensate pump is simply directed by that small tube back into the same drain line.

Ultimately that system is likely to just overflow onto the floor.

The intent is for the condensate pump's outlet tube to be directed to a suitable building drain such as a waste line (with trap and air-gap) or to a floor drain.

On 2022-05-20 by J Burrows

My condensate pump appears to be draining into itself. This doesn't seem normal. Been in house for a year with no issue untill now. The central air shut off because it was continuously pumping water.

I drained the pump and put the hose back but it keeps filling up. The float and check valve appear to be working properly.

On 2022-01-25 by Inspectapedia Com Moderator - condensate pump setup

@Bethany,

I can't see all of your condensate pump connections clearly.

The set-up should be easy:

The condensate drain from your air conditioner or heat pump drains into an opening on the pump reservoir, and the pump's output connection is piped to an acceptable drain point.

When you say "leaking" or "water not going into the pump" that's not enough data for me to know what's wrong.

If water enters the pump reservoir, does the pump turn and pump successfully to a drain? Does water drain BACK into the condensate pump from its outlet?

What's going on?

On 2022-01-25 by Bethany

Having problem with leaking. Water doesn’t go into pump. Before taking apart to clean, does this setup look right?

On 2022-01-02 by Inspectapedia Com Moderator - condensate pump drain hose needs to withstand freezing temperatures

@bOB g.,

I'm not an expert on this point so what follows is just my opinion based on my own experience.

I don't think the insulating the condensate drain is going to do the trick.

Even if you go to a plastic or silicone hose that won't itself be damaged by freezing your going to have a problem with frozen condensate.

Consider that typically condensate is draining at a very slow rate. That means that at the mouth of the drain opening, exposed to freezing temperatures, the condensate will itself freeze and ultimately block the drain.

You're probably going to need to use a heat tape.

On 2022-01-02 by bOB g.

My condensate pump drain hose needs to withstand freezing temperatures. I live in Canada. My pump is a "Little Giant -VCMA-15 ULS. Is it silicone or do I need to find a way of insulating the outdoor portion of the hose?

On 2021-10-09 by inspectapedia.com.moderator - a condensing gas furnace produces some condensate

@wingsphan1305,

I'm guessing that your gas furnace is a condensing model (high efficiency) ;

Consider that if we had PERFECT combustion when burning natural gas or propane, the only two waste products would be CO2 (carbon dioxide() and water vapor.

A condensing gas furnace produces some condensate or "water" in normal operation.

That condensate has to be drained to a suitable location; in your case your system's condensate outlet is probably lower than any nearby building drain so your installer used a condensate pump to lift that wastewater up to a building drain.

On 2021-10-09 by wingsphan1305

I don't have Central air, so why do I have a Air conditioner condensate pump connected to my gas furnace? I do not have air-conditioning setting on my thermostat either.

On 2020-12-20 by danjoefriedman (mod)

If condensate empties outside and does not wet or damage the equipment, that may be OK as a temp fix. Is there a risk of freezing?

On 2020-12-19 by Patricia

My condensate pump is broke it’s s gas furnace no A/C rerouted the condinstate outside I have no further leaking my furnace is upstairs in a attic. Is this fix ok?

On 2020-12-20 by danjoefriedman (mod) - Little Giant 554425 (for gas furnace) condensate pump

Keep in mind that I don't know what thing about you installation in there could be safety or functional concerns. I don't obviously know just your text. You will want a service technician to fix the system.

On 2020-11-03 by Ryan

Why would an HVAC installer wire a Little Giant 554425(for gas furnace) condensate pump in PARALLEL(directly to the common and power lugs) with the T-Stat?

On 2020-10-02 - by (mod) - Is it ok to use your condensate pump without the check valve

Harold:

You can use a condensate pump without check valve provided that the length of vertical tubing between the condensate pump outlet and the drain into which the pump is sending condensate is very short - just a few inches - AND that there is an air gap between the condensate pump drain tubing outlet and the drain into which it opens.

Why is a check valve needed on most condensate pumps?

If there is a greater length of rising tubing above the condensate pump then at the end of each condensate pump on-cycle the tubing contains a lot of condensate that simply drains back into the pump reservoir. The result is short-cycling or very-frequent condensate pump "on" cycles that can burn out the pump motor.

If there is no air gap between the end of the condensate drain tubing and the drain into which it empties there is risk of back-siphoning from the drain into the condensate pump, risking unsafe, un-healthy, even dangerous bacteria and gases into the condensate handling system and in some arrangements even into the building itself.

On 2020-10-02 by Harold koch

Is it ok to use your condensate pump without the check valve, I had a problem with the valve not functioning properly and couldn't find one so I used air pressure and intentionally blew out the check ball inside the valve,since then I haven't heard it kick on,will it be ok to run my furnace

On 2020-09-02 by Anonymous

Yes you can

On 2020-09-02 by Nina Foglesong

Can I use a 3-way valve on the drain line that exits a condensate pump to direct the water outside the house in the summer and inside to my sump pump hole in the winter?

On 2020-08-21 by anthony

can 4 condensate pumps discharge into the same 3/8" plastic tubing then discharge to an outside location . what prevents the condensate discharge from feeding back to the other pumps.

On 2020-05-31 - by (mod) - Is there a battery or solar back up solution for maintain power to my condensate pump ?

Yes there are definitely battery backup pumps for most applications.

However with power off I would expect the air conditioning system not to be working in there for the condensate production would also be expected to stop.

So please clarify what's actually happening at your building. And I can comment further.

On 2020-05-31 by Chris

My condensate pump overflows when the power goes off.

Is there a battery or solar back up solution for maintain power to my condensate pump or maybe there is a pump with this feature designed into it?

Chris

On 2019-07-27 - by (mod) -

Sorry I don't know what AVC valve is

Perhaps you could post a photo

On 2019-07-26 2 by Janet

My vc valve snapped off when i was trying to change it. How do i get it out

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:

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

Reply:

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.

Question:

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

Reply:

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 GUIDE A/C or 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.

Reply:

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

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..

Reply:

Charles,

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.

Reply:

(Aug 7, 2012) (mod) said:

David

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?

Reply:

Dee,

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.

• Franklin Electric, 9255 Coverdale Road Fort Wayne Indiana 46809 U.S.A. +1 260-824-2900 phone +1 260-824-2909 fax Website: franklin-electric.com

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?

Reply:

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 arose...my 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.

Reply:

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 searching inspectApedia for

DIAGNOSTIC GUIDES A/C / HEAT PUMP

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?

Reply:

Pete

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?

Reply:

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.
Thoughts?

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.
flag like

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

Reply:

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?

Reply:

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?

Reply:

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 ?

Reply:

(mod) said:
Find and unclog a blocked condensate drain; search InspectApedia.com 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.

Reply:

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

...

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

Or see CONDENSATE PUMP FAQs-2 - more-recent Q&A about using and installing or fixing A/C condensate pumps

Or see these

Recommended 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

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

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