How to Replace a Broken Air Conditioner Condensate Pump

The house was a bit warm so I set the temperature a couple of degrees lower on the thermostat. A short while later, I noticed that no air was coming from the registers and the outside compressor unit wasn’t running. The problem was caused by a broken condensation pump which triggered the overflow safety switch to shutoff the AC.


Purpose of an Air Conditioner Condensation Pump

An air conditioner condensate pump is used when a gravity (or downhill sloping) condensate drain line to either the outdoors or a floor drain isn’t feasible, for example when the air handler is located in the basement. (My home has two air handlers: one in the attic with gravity condensate drain line to the outdoors and another in the basement with a condensate pump.)

The pump reservoir collects the condensate water from the air conditioner evaporator coil drain line in the warm season and/or the excess water from the whole house humidifier mounted to the air handler in the cold season. A float switch activates the condensate pump when the reservoir is full to pump out the water to an overhead sewer line or drain some distance away. If the water level rises to the high water mark, the float switch will activate a safety cutoff relay to turn off the air conditioner to prevent flooding.

My air handler is located in the basement and the condensate pump drain line is connected a brass tee fitting on top of the overhead sewer line:

HVAC Condensate Drain Tube Sewer Line Connection

HVAC Condensate Drain Tube Sewer Line Connection

How to Replace a Broken Air Conditioner Condensate Pump

I performed a couple of quick diagnostic checks on the air handler:

  1. The thermostat relay was making an audible “click” when the temperature setting is lowered and the electronic display said the system was ON. This is good.
  2. The main circuit breakers for the inside air handler and outside compressor were not tripped, so the power wasn’t the problem.
  3. Taking a look at the condensate removal pump on the basement floor next to the air handler, I noticed it was full of water. The safety cutoff float switch had tripped due to the high water level to turn off the A/C system to prevent flooding.
Little Giant Automatic Condensate Removal Pump VCL-24ULS

Little Giant Automatic Condensate Removal Pump VCL-24ULS

Oh great!” I thought to myself. It’s Sunday night and the hardware stores are all closed. There’s no chance of getting a replacement condensate pump tonight. I could call an A/C repairman for an after-hours visit – but there was another less expensive solution…

Temporary Fix for Broken Condensate Pump

As a temporary fix for the broken pump so I wouldn’t be sweating all night:

  1. I unplugged the condensate pump.
  2. Removed the four corner screws to the cover of the pump.
  3. Removed the cover with the pump motor and mechanism off the water reservoir.
  4. Carried the water reservoir outside and dumped the water.
  5. Reassembled the pump.
  6. Plugged in the pump power cord.

The float switch reset itself now that the pump reservoir was empty allowing the A/C system to operate. The air conditioner will run for several hours until the reservoir was full again. With the cooler outside temperature that night, the A/C reservoir was only 1/2 full the next morning.

Replacement Condensate Pump

The big box hardware stores in my area have condensate removal pumps, but not the brand or horsepower rating of the pump that I have. The online product reviews for the pumps in the big box stores were negative, so I nixed the idea of buying a cheaper (~$70) pump that had a bad reputation.

My pump is a Little Giant Pump Company model VCL-24ULS with a 1/18 HP motor, 1 gallon water tank and will lift 150 gallons of water per hour to 16 feet high.

If you’re looking for a wiring diagram, see the Operating and Maintenance manual.

Little Giant Condensate Removal Pump

Little Giant Condensate Removal Pump

The new condensation pump, installation instructions and sticker with a notice to clean the pump when changing the AC/Heater filters.

Little Giant Condensate Removal Pump VCL-24ULS

Little Giant Condensate Removal Pump VCL-24ULS

Install the New Condensate Pump

The new pump was simple to install and the job took no more than 10 minutes.

Here are the new and old pumps. The old pump died after almost 9 years. The dusty look of the old pump is from overspray when the contractor painted the drywall when the house was built.

Old and New Air Conditioner Condensation Pumps

Old and New Air Conditioner Condensation Pumps

Remove the Old Condensate Pump

My pump has two input lines:

  • Rigid white 3/4 inch PVC drain pipe from the A/C unit
  • 3/8 inch clear flexible tube from the humidifier (used in the winter with heating)

and one discharge line:

  • a clear 3/8 inch flexible discharge tube that connects to the overhead sewer line

To remove the old pump:

  1. Turn off the AC/heater system at the thermostat.
  2. Disconnect the power cord to the pump.
  3. Remove the wire nuts that connect the AC/heater safety shutoff wires to the float switch. This is a low voltage circuit – typically between 12 and 24 volts.
  4. Remove the flexible 3/8 inch discharge tube from the barbed nipple.
  5. Remove the four cover screws at the corners of the pump.
  6. Lift up the pump cover and slide the water reservoir away from the the PVC drain pipe.
    I needed to remove the cover because the rigid 3/4 inch PVC drain pipe extended an inch or two below the cover and I needed to tilt the reservoir to clear the pipe.
  7. Clean the drain pipe and lines with bleach and water.
  8. Set the new pump in place.
  9. Reconnect the drain and discharge lines.
  10. Reconnect the safety shutoff switch wires.
  11. Reconnect the power to the pump.
  12. Turn on the AC/heater at the thermostat.
  13. Fill the pump basin with water and test.
Disconnect the Condensate Pump Fill and Drain Lines

Disconnect the Condensate Pump Fill and Drain Lines

Remove the cover screws and lift off the pump.

Remove the Air Conditioner Condensate Pump Cover

Remove the Air Conditioner Condensate Pump Cover

Yuck! Everything is covered in crud. It’s remarkable the pump lasted almost 9 years. I see why the new pump includes a sticker for the service technician to clean the pump and basin when changing the AC/heater air filters.

Old Condensate Pump Covered in Crud

Old Condensate Pump Covered in Crud

I removed the cover of the new pump because the instructions indicated there might be packing material inside. I found none.

Note that the pump has two float switches (click on the image below for a full size view):

  • Float for the high-water safety cutoff switch. The switch controls a low voltage circuit. When the switch is triggered, the air conditioning unit will shut down to prevent flooding.
  • Float for the On/Off switch. This float rises and falls with the water level in the basin. When the high water mark is reached, it triggers the pump On switch to pump out the condensate water.
Air Conditioner Condensate Pump Floats

Air Conditioner Condensate Pump Floats

The new pump was simple to install. Just reattach the safety cutoff switch wires (yellow wire nuts – the order of the wires doesn’t matter, it’s a simple contact closure switch), insert the drain lines and reattach the discharge line to the barbed nipple. I filled the pump with water through the hole at the front-right corner to check the operation and look for leaks around the barbed nipple. Everything worked fine!

New Condensate Removal Pump Ready for Service

New Condensate Removal Pump Ready for Service

Note to self: Clean the condensate pump each time the AC/heater air filters are changed.

Cause of the Old Pump Malfunction

The cause of the malfunction was the extensive build-up of crud on the float shaft. This prevented the On/Off float from rising with the water level to turn on the motor. The float would move with hand pressure, but it was too stiff for its natural buoyancy to lift with the rising water level.

Now when I change the A/C air filter, I also clean the condensate pump. To clean the pump:

  • Turn off the A/C unit.
  • Unplug the pump power cord. Water and electricity don’t mix!
  • Remove the four screws from the metal cover.
  • Wash the basin with soap and warm water.
  • Wash and wipe down the submerged parts of the pump.

I paid particular attention to wiping down the metal float shaft and checking that it moves freely.

You can find a wide variety of Little Giant and other Condensate Removal Pumps at Amazon.com.

Hope this saves you some buck$.

Bob Jackson

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52 Responses to How to Replace a Broken Air Conditioner Condensate Pump

  1. Estetik June 4, 2009 at 6:55 am #

    How to Replace a Broken Air Conditioner Condensate Pump | HandymanHowto.com great article thank you.

  2. Arthur July 30, 2009 at 2:26 pm #

    Excellent work. Thank you for detailed explanations, pictures and diagrams.
    Please continue. My next project is replacing condensation pump, and I feel more confident after reading your site.

  3. Nick January 18, 2010 at 2:54 pm #

    Great explanation. I thought there was a float switch in there, but none of the manufacturers discuss it online. Your description assured me it was a good idea to open up the pump – sure enough, the float switch was junked over and all I needed to do was clean it. Works like a charm now! Another good thing to always do, half a cup of bleach into the condensate drain every time you replace a filter. Thanks again!

    • Bob Jackson January 18, 2010 at 6:08 pm #

      Thanks for letting me the article helped you. – Bob Jackson

  4. Karen February 28, 2010 at 4:10 pm #

    Thank you so much for your help. I was so glad I found your article because I had no idea what to do when the unit was leaking. Haven’t tried the repair yet, but even if it doesn’t work I also know how to install a new one. Keep up the great work !!

  5. not too handy May 5, 2010 at 10:39 am #

    Found water on the basement floor – pump running constantly – turning off/on thermostat and unplugging pump power did not help. Searched online and found your article – tho my pump is not the same and smaller – the principle should be the same so I’ve opened the assembly – it has crud but not bad enough – float seems to move freely too – BUT after emptying the container – found a small frog floating in the water;must have been the obstraction that’s preventing the float to function. Re-installed unit – seems fine now.

  6. Chris Golden May 26, 2010 at 1:56 am #

    This was an awesome article, and it seemed to be pointed right at me. Love it!!! Thanks

    • Bob Jackson May 26, 2010 at 4:31 am #

      You’re welcome. It’s amazing what you can find on the web on just about any topic.

  7. Friendo July 7, 2010 at 8:58 am #

    Thanks for this write-up. My pump and the tubing that connects the A/C to the pump seem to be fine, however, the tubing that removes the water from the pump popped off on the sump side. We’ve been running it longer than usual so it might have just hit it’s wear point. The ring fastener looks OK, so I think I just need a replacement tube.

    Until I get to the hardware store, I was able to soak up the water with a towel and get it 99% dry and hopefully let the A/C run for a bit without spraying water everywhere.

    Thank you again for a great write-up.

  8. mstrini September 2, 2010 at 12:25 pm #

    Thank you so much for this article. My basement has been flooding for the last month on random days of the week. I initially called to HVAC folks to look at the air conditioner unit and after being told it may have been clogged, they cleaned the clog and left. Two days later I called again after the flooding re-occurred. I was told they found nothing and left. A week and a half later I called again to be told to look at my water conditioner system which happens to be in the same area. I was told to look at the backwash day and see if the flooding happens around the same time. Since then I have run the backwash on a day when I was home to observe it and everything was fine. On Monday I came home to see the PVC leading to the condensate pump disconnected and water over everything. I fixed that and glued the PVC back together and thought, finally, I have fixed the problem. Then today, my Mother called me at work to say the flooding occurred again. This frustrated me so much I started to look for a license water treatment contractor. One of my handyman friends said he was 99% sure is was not the water treatment system, but the float in the condensate box. I started googling the internet and came upon your handout. I was so so frustrated, but after reading your pamphlet (by the way my condensate box is the same as your new one) I feel confident I can go home today and fix my problem once and for all (be it the float or replacement). So with that, (I know this is lengthy but you have to feel my frustration) I will again say THANK YOU! THANK YOU!

    P.S. I have made this website a favorite.

    Ms Trini.

    • Bob Jackson September 2, 2010 at 6:57 pm #

      Thanks for taking the time to write and letting me know my “How To” project helped you.
      Bob

  9. mstrini September 10, 2010 at 1:45 pm #

    Bob,

    As of today,10 September, my basement floor is DRY. For a little more assurance, I went ahead and puchased a “wet alarm” so at least I’ll receive an audible alert if it happens in the future.

    But you know the way things work? Now that I have the alarm there will be no more instances…I can live with that.

  10. Lynna September 23, 2010 at 2:11 pm #

    THANK YOU …………

  11. David October 14, 2010 at 10:18 pm #

    Thank you! I have a slightly different model – but this was exactly my problem, and solution as well. After 10 years of not knowing to clean this, I discovered my basin was filled almost half way with mud.

  12. JP December 3, 2010 at 11:29 pm #

    How is it that the water is pulled into the basin from the heater/AC? I’ve had condensate pools of water near the base of my chimney when the heater is running alot, however the basin for my condenstate pump is always bone dry (winter and summer)? Does the pump unit have anything to do with drawing in the condensate and mine is just not functioning/clogged? Not sure if there is any water in the PVC line either, but what is the inside the vent collecting condensate to darw into the pump basin?

    • Bob Jackson December 4, 2010 at 11:26 am #

      > condensate pools of water near the base of my chimney when the heater is running alot,
      > however the basin for my condensate pump is always bone dry (winter and summer)

      You may have one or more of these problems:
      1) If the furnace is a standard non-condensing type, water may condensing inside the gas flue vent pipes and dripping down the chimney.

      2) If the furnace is a high-efficiency condensing type, the condensate drain pan outlet or drain pipe may be clogged.

      3) The evaporator coil condensate drain pan outlet is clogged – this only a problem when you run the air conditioner in the summer.

      Problem #1 means there’s something wrong with the gas flue exhaust pipe that’s allowing the combustion gases to cool enough for the water vapor to condense inside the pipe. Your flue vent pipes may be too large (causing the gases to move too slowly) or the vent pipes are too long (allowing the exhaust gases to cool too much). You’ll need to consult an HVAC professional to determine if there’s a design or installation problem. You can read more about Type B gas flue vents in this article.

      Problems #2 and #3 have the same root cause: the condensate drain pan and/or drain pipe is clogged.

      Water drains by gravity from the evaporator coil condensate pan through the PVC drain pipe to the holding tank of the condensate pump. I’ve annotated the condensate pump drain lines in this illustration:

      > however the basin for my condensate pump is always bone dry (winter and summer)?
      The drain outlet on your condensate pan and/or the pipe itself is clogged, causing the pan to overflow. The water is running down the inside of your air handler and onto the floor.

      See this article for instructions on cleaning the evaporator coils. You’ll be able to to inspect the condensate pan and drain outlet.

  13. Jeff June 2, 2011 at 8:52 am #

    Thanks for the step by step details. That is really lacking on most “how-to” sites.

    I usually clean the tank out about once a year and pour bleach down the tube every month or so.

    Last month the HVAC tech from the a/c company came out to do the spring maintenance check up. They dump a cleaner down the pvc condensate drain pipe from the a/c to the pump.

    The last week or so the pump has been running constantly, by constantly I mean the pump runs for 15 secs, shuts off for about 1 min, runs again. I cleaned the tank out in the middle of the night a few days ago. I found the cleaner had formed in to a solid, like Styrofoam, and a dead roach floating inside. I cleaned the tank and blew some canned compressed air in the pump area. The next day when the condensate accumulated, the pump started to run constantly again. So I ordered a new Little Giant VCMA-20ULS. I only have roughly 5′ to pump vertically and 10’+/- horizontally to the sewer drain vent in the attic.

    Thanks for the info on the wiring for the safety switch. I was worried about polarity.
    Jeff

  14. Kim June 7, 2011 at 12:46 pm #

    Wonderful, wonderful, wonderful. When I went to the store to get the new pump, I knew exactly what to ask for. Great pics. Very Helpful.

  15. Jeff June 12, 2011 at 2:40 pm #

    Update:
    Since I last posted, I learned a few things. Hooking up to a sewer vent without a p trap is bad news, and from a few sites it’s wrong/ against codes to hook up to a sewer vent period. This is due to the sewer gases entering in your home from a open or dry condensate line. I bought some clear 3/8″ vinyl tubing and ran it from the old pump to a existing hole on the underside of the eave of the roof outside. I plugged the drain to the sewer vent.

    Now I’m watering my bed of plants with the condensate from the a/c. I’m keeping my new pump as backup.

    • Bob Jackson June 12, 2011 at 6:43 pm #

      > Hooking up to a sewer vent without a p trap is bad news…
      That is correct, the purpose of a sewer vent is to relieve the vacuum in the pipe to prevent the p-trap from siphoning dry.

      > ran [the line] to an existing hole on the underside of the eave of the roof outside.
      That should be OK since the air conditioner won’t be running when it’s cold outside so the line freeze.

      Running the line outside won’t work if you have a natural gas condensing furnace or a whole house humidifier. A condensing furnace generates condensate by cooling the hot flue gases to recover the heat of evaporation from the water vapor in the combustion products for higher efficiency. My natural gas furnace isn’t a condensing model, but I do have a whole house humidifier in the main plenum that runs in the winter months when the furnace is on. The overflow water from the humidifier runs to the condensate drain pump. So if one has a condensing furnace or a whole house humidifier and you live where it freezes in the winter, the condensate drain line can’t be routed to the outdoors or the line will freeze, the condensate pump reservoir will fill up and the float switch will turn off the furnace. Then really bad things start to happen – like you’re away visiting relatives for a few days, the house gets really cold, then the water pipes freeze and burst for a New Years Day Flood! (Bad stuff always happens during the holidays.)

      The solution for condensing furnaces and whole house humidifiers in freezing climates is to route the condensate drain pump line to an inside sewer line. My home is done this way using a PVC ell and a couple of PVC adapters to a barbed brass fitting.

      There are two ways to tap into an existing sewer line: install a PVC clamp-on saddle (consult with a plumber before doing this to ensure it meets code) or cut the line and install an ell to accept the adapter and barbed brass fitting.

      Thanks for posting back,
      Bob Jackson

  16. Jeff June 15, 2011 at 10:37 am #

    Thanks Bob,
    I have an Induced Gas Furnace and I live on the Gulf Coast where it only freezes a couple times a season.
    Jeff

    • Bob Jackson June 15, 2011 at 4:23 pm #

      You’re situation on the coast won’t be a problem. I took time to explain the potential freezing problem with condensing furnace and whole house humidifier for the benefit of other readers.
      Thanks

  17. Bran Koch June 18, 2011 at 11:59 am #

    My condensate pump seems to run all the time. I opened the pump and the holding tank has only a 1/4 inch of water in it and it is quite dirty. I checked the float switch and the motor goes on when the water is low and shuts off when the float is high. This seems opposite of what it should do. Am I understanding it correctly and if so, have you any ideas?

    Thanks

    • Bob Jackson June 18, 2011 at 2:08 pm #

      The float actuates a relay switch to turn on the pump motor when the water is high. There are four float switch positions:
      1) Empty water mark – Pump turns off when the float switch hits the empty position.
      2) Normal water range – between Empty and Full; pump is off waiting for the reservoir to fill.
      3) High water mark – condensate reservoir is full, pump turns on, float switch falls until it hits the empty water mark.
      4) Safety Shutoff water mark – The high water mark is exceeded, pump not working, safety overflow shutoff triggered to turn off the AC unit to prevent flooding the room.

      > My condensate pump seems to run all the time… I checked the float switch and
      > the motor goes on when the water is low and shuts off when the float is high.
      As you said, the pump is dirty. The float arm is probably sticking at the high water mark (position #3) keeping the motor on. The motor turns off at the extreme high side because you’re moved the float to Safety Shutoff position #4.

      You could try cleaning the crud off everything so the float arm moves freely, however these small pumps are not designed for repair and it’s best to simply buy a new pump.

  18. Sue July 8, 2011 at 10:32 pm #

    This isn’t the first time I’ve had problems with this old pump. It’s at least 13 years old – that’s how long I’ve been in the house. I cleaned it tonight after finding water on the basement floor and a reservoir full of gunky water. It still won’t turn on. Out to buy a new one tomorrow.

    My old unit doesn’t have the safety cut-off switch wires. Do all newer models have them? If so, will the directions tell me what to connect them to on my system? (It’s at least 22 years old – I know I need a new one but can’t afford it right now.) I pride myself on learning how to do things on my own – is this as manageable as you make it sound? Thanks for any help you can give me!

    • Bob Jackson July 9, 2011 at 10:38 am #

      If a safety cutoff switch isn’t included with the pump, it’s usually available as an accessory for around $10 to $15. I highly recommend buying a pump that includes an internal safety switch. It’s possible you already have an external safety switch in the condensate drain line; however drain line cutoff switches are most commonly found on gravity drain systems that don’t require a pump.

      Pump manufacturer wiring instructions vary greatly in the level of detail and usually recommend consulting your air conditioner’s operating manual. The safety switch is typically wired into the low voltage thermostat circuit as shown in Figure 2 of this installation manual. The float switch as shown in Figure 2 will be “normally closed” and if the water level gets too high, the float switch will trigger and open to disrupt the thermostat circuit causing the air conditioner to turn off.

      If in doubt, consult an HVAC professional as the cost for wiring in the float switch would likely be the minimum charge for a service call.

  19. Jim Hollinsgworth July 18, 2011 at 3:07 pm #

    Mr. Jackson,

    Enjoyed the self help article on condensate pump replacement. Annual inspection and cleaning inside the pump tank, around the float, check valve (if installed), pump head components and discharge line is very important to keep the pump in tip top condition. A well maintained condensate pump will last longer than the air conditioner. Job well done.

    Regards,

    J Hollingsworth

    • Bob Jackson July 18, 2011 at 5:05 pm #

      That’s real street cred coming from the Product Manager at Franklin Electric – the manufacturer of Little Giant condensate pumps!

      Thanks!

  20. JJP in NJ August 12, 2011 at 8:27 pm #

    Excellent write-up. I just emptied my condensate pump (using a 60cc syringe and a bucket) and the AC kicked on. I come up and read this article and it’s exactly my issue. Now I just have to figure out if there is a clog, a bad float (the pump was running continuously with noting coming out). My drainage tubing to my sewer line is bone dry and it feels like there is a vacuum in there as the end close to the sewer drain has a bend and that feels or looks like it is a vacuum like kink. Also my pump appears to be plugged inside the furnace above the blower like it might be hard to get to–this will complicate turning off the pump to clean it and check it for clogs or malfunction. So I have my work cut out for me.

  21. Jay Torchio August 13, 2011 at 3:57 pm #

    EXCELLENT article! As previous posters have indicated – such a great resource. Thank you for all the time and effort you’ve put in. Quick question for you (or others). I just had a Little Giant Condensate pump put in (model #554425). I see that one of the keys to a long lasting pump is cleaning it periodically. Unfortunately, I have NO idea how to access the inside of the reservoir on this unit. There is only one screw that is visible from the top. When I unscrewed it, the cover came off but exposed what seemed to be the motor and other electrical parts. At that point, I thought it best to put the cover back on and do a little more research. On this model, am I relegated to just pulling one of the caps out and putting a little bleach? Any advice would be much appreciated. I called the Little Giant people but they’re not open until Monday and my neurotic nature makes it difficult to wait until then. :-)

    • Bob Jackson August 14, 2011 at 6:59 am #

      As best I can tell from the owner’s manual drawings, it appears the pump cover snaps on to the tank. Page 2 of the pump manual clearly says to remove the motor/pump cover for testing and cleaning – it’s just doesn’t say how to remove the cover. If the cover won’t snap off without damaging the unit, best to wait until you can speak with Customer Service on Monday.

      Thanks for reading!

  22. Joe August 27, 2011 at 7:42 pm #

    Thanks for all of this useful information, Bob; we recently had a new HVAC installed in our home, and the installers routed the PVCI tube from the Utilitech condensate pump to drain out through one of the basement vents under our deck.

    We live in North Carolina so we do stand a chance of condensate freezing in the line. Am I correct in assuming that it would be unsafe to route the PVCI tube into an open sump pump reservoir in our basement?

    By the way, we’re on septic if that has any bearing on any of this. Thanks in advance for any insight you can provide.

    – Joe

    • Bob Jackson August 28, 2011 at 8:25 am #

      If the condensate drain tube is properly sloped the last few feet as it exits the house under the deck, then there won’t be standing water in the tube to freeze. The concern I have is the water is being dumped next to the foundation in a dark place under your deck – persistently damp ground invites termites and rot.

      > Am I correct in assuming that it would be unsafe to route the PVCI tube into an open sump pump reservoir in our basement?
      That would be fine if there’s an air gap between the tube and water level in sump pump reservoir. You don’t want the tube to be submerged which will invite algae growth and clog it up. For example, if you have a grate over floor drain, it’s OK to lay the tube on the grate.

      > By the way, we’re on septic if that has any bearing on any of this.
      Septic is fine. The air conditioner will produce between 5 to 20 gallons per day of condensate water – that’s about the amount of water used when taking a shower. The big concern with septic tanks is to minimize the organic load on the system – table scraps go into the trash can instead of down the garbage disposal – to protect the drain field and maximize the time between visits by the honey truck.

  23. Joe September 10, 2011 at 8:13 pm #

    Thanks very much for providing these useful insights, Bob. This should work with the system we have; I don’t see any reason now not to run the condensate pump into the sump reservoir (plenty of room to spare) – the last thing we need to do is encourage termites.

    Also, my apologies for not replying to your message before now; I thought there was an email alert for this thread, and I only just remembered to check for your response while I was actually in front of the computer.

    Thanks again – have a great weekend!

    – Joe

  24. Kevin p July 23, 2012 at 7:15 am #

    My problem seems a little different, the condensate pump drain line is completely compressed, basically flat. I can see a small amount of water moving through the line but water is already spilling over the sides of the pump. The hvac guy says the line needs to be replaced, he said the lump is fine but I would tent to look at the pump as the source of the problem. To replace the line in the basement we will need to remove sheetrock to run the new line. My question, should I replace the pump and or the line? Wih a new pump will the line expand again? I beleive by code the line is run outside, but can I drain it into another line in the basement safely, I probably won’t because of the code, but just checking.

    Just seems like a big expense to install a little plastic line and the house under two years old.

    Thanks for the great article!

    • Bob Jackson July 23, 2012 at 6:20 pm #

      To check the pump operation, attach a new length of discharge line tubing to the pump outlet and run it into a bucket. If the pump is moving a strong stream of water, then the pump is probably OK. A more realistic test would be to loop a 15 foot section of new tubing from the pump over the top of a step ladder and back down to a bucket on the floor. The pump will have to overcome a 7 foot “head” of water pressure. A taller ladder or maybe loop the tubing over a hook near the ceiling is an even better gauge of the pumps ability to work against the head, or column of water pressure. A condensation pump in good working order will push the water uphill with no problem. Lookup the model # on your pump to see that it’s rated for the head-of-water (vertical feet) that it needs to pump the water uphill.

      Are you able to trace the discharge line to the outlet? It shouldn’t be collapsing as you describe unless it’s clogged. If you can follow the line, look for any kinks or maybe algae clogs. You could try blowing the line clear with a rubber nozzle on a portable air compressor. Dial the compressor hose gauge down to 10 or 15 psi so you don’t burst the tubing if it’s really clogged. Have someone watch the discharge end of the tube to see if water, air and crud is blown out. I would think that replacing the discharge line would be similar to pulling (or fishing) electrical cable in the drywall. Use the original tubing to pull the new tube. Worst case, you can pull new tubing by cutting small access ports in the drywall to avoid ripping open a floor to ceiling section of drywall.

  25. mary August 1, 2012 at 5:23 am #

    how long does a condesate pump last. small house one yellow color

    • Bob Jackson August 1, 2012 at 7:08 am #

      It varies with the how well the pump is maintained and how much the pump is operating. A home in a southern climate where the air conditioner runs for a longer part of the year will wear out sooner. My pump lasted about 10 years. The motor still worked fine, but the switch float deteriorated and submerged parts were coated with sludge.

  26. Jerry D. September 1, 2012 at 9:07 pm #

    The last time my repairman took the pump apart and I clean all the muck out. Started to have issue water leaking out of unit etc. Come to find out the hose and the elbow coming out of the drain was clogged. Don’t forget to clean the hose when you clean the pump.

  27. Michael Henderson June 18, 2013 at 2:56 pm #

    https://www.dropbox.com/s/wv0evyeiyl2xnkz/fanswitch1.jpg

    Hi, I hope you see this soon and can reply. Above is a link to a pic I took in the area of my condense pump. That fan switch looking thing is actually wired between the wires that come from the pump and the wires that go to the AC unit. If the pump has its own safety shut off, then what is that thing? Recently the place backed up with water some when the pump failed, or the lines actually clogged.I dint know if that switch looking thing may be the reason that the safety switch didnt kick in. Can you tell me what that is and when i change out the pump should i just remove that?

    • BobJackson June 18, 2013 at 5:56 pm #

      It’s difficult to determine what that switch-thingy is exactly, I’d need to see photos of the other side the device with a wiring diagram (hand drawn is fine) to fully understand how it’s connected between the pump and air conditioner unit. The main issue is confirming it’s wired into the safety overflow switch circuit, which carries at most 24 volts AC (alternating current).

      Is the “switch” a multi-position rotary switch or a On/Off two position switch? The “switch” appears to have three (3) wiring connections (brown, red and green), whereas a normal switch only has two wires. Are there part numbers or manufacturer markings stamped on the device?

      If you have a digital multi-meter, turn Off the circuit breaker for the air handler and unplug the condensate pump from the wall outlet. Use the multi-meter to check for continuity across the “switch” when the switch lever is set in different positions. This will determine if it’s really an On/Off switch or something else. Set the switch lever back to the original position before turning on the power.

      If in doubt, call a licensed HVAC technician to identify what it is. A service call should run less than $100 and it’s better than damaging the condensate pump or AC unit.

  28. Rod Cohen August 31, 2013 at 2:52 pm #

    My old pump appears to have not only 110 wires going to it, but it also appears to the safety switch and then another pair of low votage wires going to it. I do not know what to connect to the safety switch and the little giant pump I bought does not have another set of wires.

    Any thoughts on this? i can provide pictures.

    • BobJackson September 3, 2013 at 5:14 pm #

      What is the Little Giant condensate pump model number? Need to study the new pump wiring instructions, then figure out what the extra set of wires are for with your air handler. Photos would help, send to bob (at) handymanhowto.com. Replace the (at) with an @ symbol.

      Sorry for the delay getting back to you with the holiday weekend.

  29. Brad - VA June 27, 2014 at 11:28 am #

    Great article, I am working to update my home of 10 years to rent it out spending thousands and doing work myself when I can. I came to the home today and the thermostat said it was 85 degrees in the house. I panicked of course noticing the outside unit was not working no matter what I did including tripping switches, pulling my thermostat off the wall, (unfortunately resetting its automatic programming.)

    I searched and found this article, which appears to be rather old… however still timely. Thanks!

    • Bob Jackson June 27, 2014 at 6:01 pm #

      You’re welcome! I updated web links that changed after Franklin Electric acquired the Little Giant Pump Company. Everything is now be up to date.

  30. Alex July 15, 2014 at 6:55 pm #

    Hey Bob, great piece. I’ll echo everyone else and say it was exactly what I was looking for.
    How can I determine if the drainage tube is clogged? My tube goes exits the pump and goes up through the ceiling, so I can’t get to where it meets the plumbing. I have an (old) heat pump/air handler, and the pan has been filling up, particularly at night. The pump works nonstop but can’t keep the pan dry, so I am trying to determine if the pump is clogged (repairman was just here and said he checked it, so hope its not that), the pump is old/not strong enough, or the drainage is not working as efficiently as it should. I definitely need a new heat pump/air handler, but would not think that in and of itself would lead to there being so much condensation that the pump couldn’t handle it. Thanks a lot!

    • Bob Jackson July 15, 2014 at 10:33 pm #

      > have an (old) heat pump/air handler, and the pan has been filling up, particularly at night.
      The condensate drain pan under the evaporator coils is filling up? And the drain pump is somewhere below the pan like on the floor? It may not be your drain pump or flexible discharge tube that’s the problem. Standing water in the drain pan indicates the rigid PVC drain pipe is clogged. If the pump weren’t working safety overflow switch would cut off the pump so the reservoir doesn’t flood. Open the evaporator coil case and check the water flow from the drain pan down the PVC drain pipe. Clogged PVC drain lines can be cleared with the Mighty Pump A/C Condensate Drain Line Pump or by sawing off the drain tube after the elbow, clearing the clogged elbow and splicing in a new section(s) of PVC pipe.

      To check the flexible drain tube:
      Is the condensate drain pump flexible tube clear or semi-transparent? Can you (partially) see through the tube if back-lighted with a flashlight? If so, disconnect the pump discharge drain tube to let the standing water flow out and reconnect the tube. The tube will be filled with air. Carefully fill the pump reservoir with water (a funnel helps) until the pump turns on and check the tube for flowing water. There should be a dividing line between the water level and air with some bubbles to the visually observe the flow rate.

      > The pump works nonstop but can’t keep the pan dry, so I am trying to determine if the pump is
      > clogged (repairman was just here and said he checked it, so hope its not that), the pump is old/not
      > strong enough, or the drainage is not working as efficiently as it should.
      You can check the condensate pump operation by purchasing some flexible tubing at the home improvement store. Buy a length that’s about equal to the height of your ceiling. Disconnect the old tube from the pump, connect the new discharge tube, stand on a ladder with a bucket at ceiling height and put the end of the new tube in the bucket. Have a helper fill the pump reservoir with water until the pump kicks on. Do you see a strong flow of water into the bucket? If not, the pump is weak because it can’t lift the water to the required “head” (height in feet).

      > My tube goes exits the pump and goes up through the ceiling,
      > so I can’t get to where it meets the plumbing.
      I had the same problem and installed a bauco rondo access panel in the drywall ceiling to access the condensate drain tube to sewer line connection. My problem is many plumbing and gas utilities were concealed when the previous homeowners finished the basement.

      If your drain tube is clogged the culprit could be the water trap loop concealed inside the ceiling.

      Let me know what you find.
      Thanks,
      Bob

      • Alex July 28, 2014 at 2:05 pm #

        Thanks a lot Bob, I appreciate all your advice. A couple of clarifications:
        1. The condensate pump sits IN the pan which surrounds the air handler. I assume it sits inside the pan because that way if it ever leaked the pan was able to capture it (more on this below).
        2. There does not seem to be water in the base of the air handler (like below the filter) when I open it up. The PVC drain pipe was recently replaced and I have opened the trap and cleaned it (not dirty).

        What appears to be happening is that the pump is filling up and excess water is flowing out of the top of the pump and into the pan, and occasionally (during a really hot week) this fills up the pan and trips the float switch that shuts off the system. What is not clear is if the discharge tube is clogged, if the pump is weak, or if the flow of water from the air handler is too great. The man who serviced it suggested that the heat pump was working “too hard” and needs to be replaced, but I don’t know if that is producing excess condensation. I emptied the discharge drain tube and while there was some particulate in the water it did not appear like it was clogged. The pump is not set up to shut off the entire system when it fills up – that only happens if the pan fills up and trips the floater switch OR if the trap on the PVC drain pipe is clogged – so when the pump fills up with water the overflow spills into the pan.

        So the pump is not clearing the water – is it possible that this is due to an old/overworked system that is generating more condensation than it should, or do you think this is simply a weak pump?

        Thank you!
        Alex

        • Bob Jackson July 28, 2014 at 7:08 pm #

          Good description – I now have a clear picture of your setup. The AC system is doing it’s job and removing water from the air. The problem is with the pump itself or a clogged discharge line. Have you tried the pump troubleshooting steps described in my previous reply? Step ladder, bucket, new discharge tube…
          Thanks,
          Bob

  31. Sara August 31, 2014 at 6:54 pm #

    Thanks for this very well written how-to. The photos were very helpful. We found a wet basement this morning. We were able to diagnose the pump was malfunctioning. We’ve been able to setup a temporary fix until we can get a new pump:

    1) rewired pump to AC ( if it’s not wired, the blower won’t operate)
    2) rerouted all drain lines to a big bucket
    3) checking the bucket every few hours to determine the condensate rate. If it’s likely to overflow overnight, we’ll shut the AC down overnight.

    Thanks again for taking the time to explain how this pump works. Kind Regards, Sara

  32. marifel September 16, 2014 at 3:34 pm #

    This is very helpful :) our air conditioner wet out two day ago :( the tank is full of water and emptied it. when I plugged in the condenser it use to make sound that you can tell it’s on but I dont hear anything. Changed the fuse, the blower works fine but no air coming out of the vent. Does this mean we need to change the condenser? please help.

    • Bob Jackson September 16, 2014 at 6:15 pm #

      >> …blower works fine but no air coming out of the vent.
      If the blower motor and fan in the indoor air handler is running then air should be blowing out the vents. It may be warm air if the compressor or fan in the outdoor condenser isn’t working, but you should feel a strong air flow nonetheless. What you may be hearing from the air handler are the groans and noises of the refrigerant circulation through the evaporator coils.

      Because no air is blowing from the air vents that means the blower motor in the air handler isn’t running. Although you emptied the condensate pump reservoir (tank) the safety overflow switch might be stuck and preventing the air handler blower motor from running. Unplug the condensate pump power cord, remove the top cover and wiggle the float switch arm back and forth until it moves freely. You might need to clean off some crud. Be careful not to disconnect the wiring to the air handler control circuit. Put the pump back together and plug it in. The air handler blower motor should now run… at least until you can purchase a new condensate pump.

      Let me know if this fixes the problem.

      Thanks,
      Bob

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