Pumps keep failing - why?

This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.

Repeated E20 drain failures on Zanussi, with pump silence on drain cycle

The problem

A Zanussi washing machine bought in May 2017 has reportedly had three drain-related failures: August 2018, March 2019 and November 2019. Each time it showed E20 and would not drain. The original poster said the pump was silent when the machine reached the drain cycle, and previous repairs involved pump replacement.

Likely cause

The strongest diagnosis in the discussion is that repeated pump replacement is unusual and the more likely underlying cause is a blockage or obstruction in the drain path or pump area, even if it has not been found previously. The accepted reply also raised uncertainty over whether replacement pumps were genuinely required each time. A programming or timing fault was suggested by the original poster’s friend, but this was not supported in the replies.

What fixed it

Recommended action was to confirm exactly what failed before replacing any more parts: establish whether the pump is actually defective or whether the machine is not draining because of an obstruction in the pump/filter/pipework. The engineer reply noted that intermittent obstructions can be hard to find and may move around inside hoses. Exact repair was not confirmed in the thread.

Checks to try

• E20 fault code displayed
• Machine would not drain
• Pump reportedly silent on drain cycle
• Previous engineer found no obstruction according to the original poster
• Accepted advice to check for blockage in the machine, pump filter and associated pipework
• Discussion considered whether the fitted pumps were genuine replacements

Parts or tools mentioned

• Drain pump