condensate pump running continuously

What to Do When Your Condensate Pump Won’t Stop Running

Condensate pumps are electrical devices used to pump the condensate produced in a heating or cooling unit into a drain. Although they are relatively simple devices, condensation pumps sometimes present functional issues. One of the most common manifestations of such an issue is when a condensate pump is running continuously.

If your condensate pump is running too often, it might be due to an issue with one of the components. This guide will let you know why your condensate pump keeps running and the steps you can take to correct the situation.

Overview of a condensate pump and how does it work?

Condensate pumps are a type of pump that is used in HVAC systems to collect condensed liquid produced by thermal systems such as refrigerators, A/C, and boilers. It is typically employed in a basement where ordinary gravity will not be able to transfer the water. If you have an air conditioner with an interior unit or a high-efficiency furnace, you need a condensate pump to eliminate the water and other condensates that build up as the system operates.Common reasons why condensate pump keep running continuously

The working process of a condensate pump is simple. Taking an air conditioning system as an example, as warm air that needs conditioning passes over a cooling coil, the hot air forms condensates on the surface of the coil which then drips into a tray that collects the liquid into the condensate pump’s reservoir.

The reservoir contains a float switch which rises with the level of water collected. When the level of water reaches the top, the float switch then triggers the pump’s electric motor. When this happens, the process of pumping the water begins and the water in the reservoir is pumped into a drainpipe, which is channeled to the exterior of the building.

7 Common Causes of a Continuously Running Condensate Pump

There are numerous reasons why your condensate pump keeps running. A condensate pump that won’t stop running could prove to be a serious issue. However, the problem can easily be fixed with some simple steps. Here are the top reasons why your condensate pump keeps running and how to fix them.

Clogged check valve

Common reasons why condensate pump keep running continuously – check valveAn issue with the check valve can cause the condensate pump to keep running. The check valve can become clogged up with dirt and grime; this causes the check valve to fail leading to the inability of the pump to stop when it should. The check valve allows water to flow in one direction towards the exterior. A weakened, defective, or clogged valve can allow water to go back into the tank and consequently cause the condensate pump to keep running

To check this problem, simply unplug the condensate pump and remove the check valve using a small wrench. Remove any dirt and clean with a soft cloth before putting it back or replace it completely with a new check valve

Blocked or damaged condensate line

A blocked or damaged condensate line can prevent the pump from properly removing excess moisture from the unit, leading to a continuously running pump.

The float switch is stuck

Common reasons why condensate pump keep running continuously – Float switchEvery condensate pump comes with a float component. A float switch is responsible for turning the condensate pump on and off. The float serves as a trigger to help drain water when it reaches a certain level. The float can sometimes become hung up and won’t get back down. If the switch is malfunctioning, it may not turn off the pump when the water has been removed, causing the pump to run continuously.

A simple fix for an immovable float is to tap on it until it can move again. Also, inspect it for cracks or damages. If the float is damaged, get it replaced.

Discharge Line

Another area of your condensate pump that can cause constant running is the discharge line. The discharge line is flexible vinyl tubing that allows the pump to send water when the condensate pump becomes full. To inspect this, take out the discharge line and remove clogs and debris that may be blocking the drain tube. Check that the discharge line is well placed

Over-sized condensate pump: An oversized condensate pump may pump out water too quickly, causing the pump to run continuously.

Leaky or damaged air ducts: Leaky or damaged air ducts can cause excess moisture buildup in your HVAC system, leading to a continuously running condensate pump.

Dirty evaporator coil: A dirty or faulty evaporator coil can cause the air conditioning unit to produce excess moisture, leading to a continuously running condensate pump.

Effects of a Continuously Running Condensate Pump

A continuously running condensate pump can have several negative effects on your HVAC system and your home or business, including:

Increased energy consumption: In some cases, a continuously running condensate pump can also be caused by a blockage in the drainage line. Over time, debris can accumulate in the drainage line, causing it to become clogged. When this happens, the water cannot flow freely through the line, and the condensate pump may run continuously in an attempt to remove the excess water from the system.

Another possible cause of a continuously running condensate pump is a malfunctioning float switch. The float switch is responsible for detecting the water level in the condensate pump reservoir and turning the pump on and off as needed. If the float switch becomes stuck in the “on” position, the condensate pump will continue to run even if there is no water in the reservoir.

How to Fix a Continuously Running Condensate Pump

If your condensate pump is running continuously, there are a few things you can do to fix the problem. Here are some steps to follow:

  1. Check the Drainage Line: Start by checking the drainage line for any blockages. If you find a blockage, try clearing it using a plumbing snake or a pressure washer. If you are unable to clear the blockage yourself, you may need to call a professional plumber for assistance.
  2. Check the Float Switch: Next, check the float switch to make sure it is functioning properly. If the switch is stuck in the “on” position, try gently tapping it to see if it will move. If the switch still does not move, you may need to replace it.
  3. Clean the Pump: Over time, the condensate pump can become clogged with debris. If this happens, you will need to clean the pump to remove the debris. Start by turning off the power to the pump, then removing the cover and cleaning out the reservoir. Use a wet/dry vacuum to remove any debris that may be inside the pump.
  4. Replace the Pump: If none of the above steps work, you may need to replace the condensate pump. Be sure to choose a pump that is the correct size for your system and that is compatible with your HVAC system.


Why is my condensate pump so loud?

Condensate pumps make noise due to high fluid velocity and hydraulics. A condensate pump may make a bit of sound when running but shouldn’t cause a distraction. The job of a condensate pump is to remove water or condensate that develops in a cooling system. Condensate pumps can sometimes become too loud as a sign of malfunctioning or clogged drain tubes. When a condensate pump discharge is blocked, the pump increases the pressure to force out water; this increased operating pressure is what creates a noisy sound.

What happens when the condensate pump fails to shut off?

If a condensate pump doesn’t stop running, it can lead to water leaks or overflow. The overall performance of the cooling unit will be interrupted and can cause adverse problems in the long run. If your condensate pump fails to shut off, it may be a defect or a clog. You should get it checked, cleaned, or replaced.

How often should a condensate pump run?

A condensate pump can run for a long period, depending on the environment and unit it is connected to. If it is connected to an air-conditioning system, then it can run several times a day, depending on the level of humidity. A continuously running condensate pump that fails to stop when it should cause the motor to burn out or even result in serious water damage to your home alongside a high energy bill.

How to tell if your condensate pump is running correctly?

The best way to know if your condensate pump is working well is to inspect the general functioning. Listen for sounds and check if the drain hole is expelling water smoothly. If you hear a strange noise or if your condensate pump is overflowing due to any reason then the pump might be faulty and needs checking.


A condensate pump may appear small when compared to other parts of your thermal appliance, but it isn’t as diminutive as it looks in function. It performs an important job of removing condensed liquid from a system.  Usually, a hung float, an obstructed discharge line, and a clogged valve are the most common reasons for the condensate pumps running continuously. A faulty condensate pump can simply be checked and repaired or replaced

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