An Indesit dishwasher not draining can quickly disrupt your kitchen routine, leaving you with a pool of dirty, stagnant water at the bottom of the appliance. Instead of panic-buying a new machine, systematic troubleshooting often reveals that the issue stems from a simple blockage or a minor component failure that you can resolve yourself.
Why is your indesit dishwasher Not draining?
When you encounter an Indesit dishwasher not draining, the problem usually boils down to a restriction in the flow of wastewater or a mechanical failure in the pumping system. The dishwasher relies on a synchronized effort between the drain pump, the filter assembly, and the drainage plumbing to expel dirty water. If any one of these components is compromised, the cycle will stop, often triggering specific error codes to alert you to the fault.
Most drainage issues are caused by food debris, broken glass, or foreign objects obstructing the path of the water. However, installation errors—such as an improper waste pipe connection—can also prevent the appliance from emptying correctly. Understanding the role of each component is the first step toward a successful repair.
The role of the filter assembly and sump
The filter assembly is your dishwasher’s first line of defense. Located at the base of the tub, it traps large food particles to prevent them from entering the pump. Over time, grease and debris can build up, creating a gelatinous barrier that water cannot pass through. Directly beneath the filter lies the sump, a basin that collects water before it is pumped out. If the sump is clogged with heavy residue or solid objects, the water remains trapped in the tub.
The drain pump and impeller
The drain pump is the heart of the drainage system. It uses a small rotating fan called an impeller to force water out of the sump and into the drain hose. If a small bone fragment or a shard of glass slips past the filter, it can physically jam the impeller, preventing it from spinning. In other cases, the pump motor itself may fail electrically, meaning it receives power but generates no movement.
Drainage plumbing and connections
Even if the machine is functioning perfectly, external plumbing issues can mimic a machine fault. The drain hose carries wastewater from the pump to your kitchen’s waste pipe. If this hose is kinked, crushed behind the machine, or blocked, water will back up. Furthermore, if you have recently installed a new kitchen, the kitchen sink spigot (the connection point under the sink) might still have a blanking plug inside. If this plastic membrane is not removed during installation, the dishwasher essentially pumps water against a brick wall.
Troubleshooting an indesit dishwasher that won’t drain
Before calling a professional, perform these checks to diagnose and potentially fix the issue. Always ensure the appliance is disconnected from the mains electricity before performing any maintenance.
Step 1: Inspect and clean the filter assembly
This is the most common cause of stagnant water.
- Open the dishwasher door and remove the bottom rack.
- Locate the cylindrical filter at the base of the tub.
- Twist the central filter counter-clockwise to unlock it and lift it out.
- Remove the flat mesh filter plate surrounding the hole.
- Rinse all parts under hot running water. Use a soft brush to scrub away any greasy residue or calcification blocking the mesh.
- Before reassembling, inspect the sump area (the hole where the filter sits) for any solid debris like cherry pits or glass.
Step 2: Check the drain hose and waste pipe connection
A physical restriction in the plumbing is a frequent culprit.
- Pull the dishwasher out gently to inspect the drain hose. Ensure it is not twisted, kinked, or trapped under the machine’s feet.
- Check the height of the hose. It should form a high loop or rise to at least the height of the worktop before connecting to the sink plumbing. This prevents waste water from the sink flowing back into the machine (siphoning).
- If connected to a kitchen sink spigot, disconnect the hose and inspect the spigot. Use a screwdriver to verify there is no blockage inside the nozzle. If it is a new installation, ensure the blanking cap has been drilled out or removed.
- Place the end of the drain hose into a bucket and run a short “Cancel/Drain” cycle. If water flows out with force, the blockage is likely in your home’s U-bend or waste pipe, not the machine.
Step 3: Verify the drain pump and impeller
If the filters and hose are clear, the drain pump might be jammed or faulty.
- Remove the water from the bottom of the machine using a sponge and a cup.
- In many Indesit models, you can access the pump chamber from inside the sump. Look for a small cover or a Torx screw securing a plastic housing within the sump well.
- Remove the cover to expose the impeller.
- Wear protective gloves and carefully rotate the impeller with your finger. It should move in distinct “steps” due to magnetic resistance. If it feels completely rigid or gritty, something is jammed.
- Use tweezers to extract any foreign objects. Broken glass is notoriously difficult to see in the dark sump, so use a flashlight.
- If the impeller spins freely but the pump still doesn’t run, the motor usually requires replacement.
Step 4: Examine the check valve
The check valve (or non-return valve) is a small rubber flap located just after the pump or within the drain hose outlet. Its job is to prevent dirty water from flowing back into the sump after the pump stops.
If this valve gets stuck in the closed position due to grease or debris, the pump cannot push water out. Conversely, if it is stuck open, water from the drain hose runs back into the machine, leading to the “stagnant water” symptom appearing shortly after a cycle finishes. Cleaning this valve usually resolves the issue.
Step 5: Flood prevention systems
Modern Indesit dishwashers are equipped with a float switch, typically located in the base tray (underneath the main tub). This is a safety device designed to detect leaks.
- How it works: If water leaks into the base of the machine, the Styrofoam float rises, activating a switch that cuts off the water inlet and forces the drain pump to run continuously.
- Symptoms: If your dishwasher is humming constantly even when turned off, or if it won’t start a cycle, the float switch might be activated.
- The Fix: You would need to tilt the machine backward (with a towel ready) to drain the water from the base tray. However, you must then find the source of the leak (e.g., a loose hose clamp or door seal) to prevent it from recurring.
Deciphering indesit error codes
When an Indesit dishwasher detects a drainage failure, it communicates via error codes. These appear on the digital display or as a sequence of flashing LED lights on the control panel.
F03 / A03 (Water drain failure)
This is the most specific code for an Indesit dishwasher not draining. It signifies that the machine has attempted to empty the water for a set period (usually a few minutes) but the pressure sensor has not detected a drop in water level.
- Likely Causes: Blocked pump, clogged filter, or blocked drain hose.
F11 (Wash pump failure)
While often related to the circulation pump, on some models, this code can indicate an issue with the pump motor circuit. If the drain pump windings are open-circuit (burnt out) or disconnected, the machine may halt with this code.
F05 (Pressure Switch / Drain Issue)
Although more common in Hotpoint (a sister brand) machines, F05 can appear on Indesit models. It indicates that the pressure switch is stuck in the “full” position, meaning the machine “thinks” it is full of water even if the pump is running. This often points to a blockage in the air chamber leading to the pressure switch or a blocked pump.
LED flashing sequences
For models without a digital screen, error codes are shown by flashing LEDs (e.g., Wash, Dry, End lights).
- A03 Equivalent: Usually indicated by the 3rd and 4th lights flashing (or a specific combination depending on the model series like the IDL or DFG series). Consult your user manual for the specific light pattern corresponding to “Drain Fault.”
Advanced troubleshooting: Electrical and sensors
If physical checks fail to resolve the issue, the problem may be electrical.
Testing the drain pump
A multimeter is required for this step.
- Disconnect power and access the pump from the underside of the machine (remove the base plate).
- Disconnect the wire harness from the pump.
- Set the multimeter to resistance (Ohms).
- Probe the two terminals on the pump motor. A healthy pump usually reads between 150 and 300 Ohms.
- If the reading is Infinity (1) or Zero (0), the pump coil is damaged and the unit must be replaced.
The pressure switch
The pressure switch tells the control board when the water has been successfully drained. It is connected to the sump via a thin plastic tube. If this tube is blocked with fat, the air pressure cannot change, and the switch remains stuck.
- Check: Remove the tube and blow through it toward the sump to clear any blockage. You should hear a bubbling sound in the sump water.
Preventing future drainage issues
Once you have resolved the immediate problem of your Indesit dishwasher not draining, regular maintenance is key to preventing a recurrence.
- Weekly Filter Clean: Make it a habit to rinse the filter assembly under a tap once a week.
- Scrape, Don’t Rinse: Scrape solid food off plates into the bin before loading. You don’t need to pre-rinse dishes (modern detergents need some dirt to work), but solid chunks like corn, bones, or napkins must be removed.
- Monthly Maintenance Wash: Run a hot cycle with a specialized dishwasher cleaner to dissolve grease deposits in the sump and hoses.
- Glass Care: Be cautious when loading delicate glassware. If a glass breaks, stop the machine immediately and painstakingly remove every shard from the sump and filter to protect the impeller.
By systematically checking the filter assembly, drain hose, and drain pump, you can fix the majority of drainage problems without the need for an expensive service call. Taking care of these components ensures your Indesit dishwasher continues to serve your kitchen efficiently for years to come.
Frequently asked questions
Why is my Indesit dishwasher not draining water?
Most drainage problems are caused by a blockage in the filter assembly, a kinked or trapped drain hose, or food debris and broken glass jamming the pump impeller. In some cases, it may be due to an installation error, such as a blanking plug remaining inside a new sink spigot connection.
What does the F03 or A03 error code mean?
These codes specifically indicate a “Water Drain Failure.” This means the dishwasher has attempted to pump out the water but the pressure sensor hasn’t detected a drop in the water level. This is usually triggered by a clogged filter, a blocked pump, or a restriction in the waste pipe.
Why is my dishwasher humming constantly even when it is turned off?
If the machine hums or the pump runs continuously even when the cycle is over, the flood prevention float switch has likely been activated. This happens when water leaks into the base tray underneath the main tub. You will need to drain the water from the base and identify the source of the leak to resolve the issue.
How can I check if the drain pump is actually broken?
After clearing any visible debris from the impeller, you can test the pump motor using a multimeter. With the power disconnected, a functional pump should show a resistance reading between 150 and 300 Ohms. A reading of zero or infinity suggests the motor coil has failed and the pump needs to be replaced.
How often should I clean the dishwasher filters?
To prevent stagnant water and bad odors, you should remove and rinse the filter assembly under hot running water once a week. Additionally, running a monthly maintenance wash on a high-temperature setting with a specialized cleaner will help dissolve grease and limescale buildup in the internal hoses.
