What this error means
Drain fault — the drain pump is running but is not moving water at the expected rate.
The E21 error on a Zanussi washing machine indicates the machine has detected drainage occurring too slowly — the pump is running but water is not being removed at the rate the control board expects. This is a flow rate fault rather than a complete drainage failure. The most common causes are a partially blocked pump filter, a drain hose that is kinked or incorrectly positioned, a household standpipe or sink waste that is beginning to block, or a pump impeller that is partially obstructed. A pump motor that is running but losing efficiency due to wear will also produce E21.
What you'll need first
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Step-by-step
Symptoms to look for
- Machine takes noticeably longer to drain than it used to
- Pump sound continues for longer than expected during drain and spin phases
- Water drains but very slowly — some water remains in the drum at the end of a programme
- E21 appears at the end of a wash or rinse cycle
How to fix it
Unplug the machine from the mains completely. Lay towels across the floor in front of the machine and place a shallow tray beneath the filter access flap. Even though E21 indicates slow rather than absent drainage, water will still be present in the drum and hose.
Open the access flap and position your tray beneath the filter cap. Turn the cap anti-clockwise by a quarter turn to begin releasing water slowly. Empty the tray, then continue unscrewing until the cap comes free. Rinse the filter under warm running water, scrubbing the mesh with a toothbrush to remove all lint, hair, and debris. Reach into the housing cavity with a torch and clear any material from around the pump entrance.
Shine a torch into the empty filter cavity and locate the impeller at the rear. Rotate it gently with one finger. It should spin with smooth, even resistance. Any catching, grinding, or stiffness in one position indicates a partial obstruction around the impeller blades.
Trace the drain hose from the machine to the standpipe or sink waste. Straighten every kink, sharp bend, and compressed section. Confirm the hose end is no more than 15 centimetres into the standpipe, is not sealed against the pipe walls, and that the hose loops to at least 60 centimetres above floor level before descending to the waste connection.
With the machine unplugged, remove the rear lower access panel if fitted. Inspect the short rubber hose between the pump outlet and the main drain hose for any collapse, kinking, or compression that restricts the flow path.
When to call an engineer
- Pump impeller turns but only with significant stiffness — partial blockage inside the pump body that cannot be cleared from the filter side
- E21 persists after filter cleaning, hose inspection, and household drain check — pump motor losing efficiency and requires replacement
- Pump outlet hose has collapsed internally and cannot be straightened
- Wiring to the pump is damaged or the connector is corroded
Frequently asked questions
What is the difference between E20 and E21 on a Zanussi washing machine?
Can a partially blocked household drain cause E21?
Does E21 mean the pump is failing?
How often should I clean the Zanussi pump filter to prevent E21?
🎯 What is likely causing this fault?
⚠️ Estimates based on common faults — not a guaranteed diagnosis. Always verify before ordering parts.
Parts you may need
Enter your model number to filter results to your exact machine
Usually found on a label inside the door frame or on the back panel of the machine.
| Part | Approx. UK Cost | Find it |
|---|---|---|
| Drain Pump | £15 - £20 | 🛒 Amazon UK → |
| Drain Pump | £15 - £20 | Find part → |
ℹ️ Prices are approximate. Always check the part number matches your model before ordering. Not sure of your model number? Find out how to locate it here.