White Knight dishwasher not draining

What is actually happening

A dishwasher drains through a filter, a pump, and then a hose that usually loops up and into the sink waste. Standing water almost always means a blockage in that path rather than a failed part — food debris in the filter and a blocked sink trap between them account for most of it. The one to check first is whether a new sink or waste disposal has been fitted, because the blanking plug in a new waste spigot is a classic.

The White Knight fault codes that point at this

A White Knight dishwasher will usually tell you what it thinks is wrong before anyone opens it up. These are the codes we hold for this make that relate to not draining:

• F02 — The dishwasher has spotted water flowing into the machine at a time when its fill valve is supposed to be shut, so it has stopped to avoid overfilling.
• F04 — The dishwasher has asked for water but the flow meter isn't seeing any coming in, so it stops rather than run dry.
• F08 — The dishwasher has lost the electrical connection to the diverter — the valve that switches water between the upper and lower spray arms — so it stops and shows the fault.

If yours is showing one of those, that is a much shorter conversation than a general fault — tell us the code when you book and the engineer can often carry the part.

The usual causes on a White Knight dishwasher

• A clogged filter and sump at the bottom of the machine
• A blocked or kinked drain hose, or a blocked sink trap where it connects
• A blanking plug left in the sink waste spigot after a new sink or disposal unit was fitted
• A failed drain pump, or one jammed with a piece of glass or a label
• A drain hose fitted without a high loop, letting waste water siphon back

What you can safely check yourself

1. Bail out the standing water, then lift out the filter assembly and clean it thoroughly
2. Check the sump underneath the filter for glass, labels and debris
3. Check the sink trap the dishwasher drains into — clearing that alone fixes a good share of these
4. If a sink or waste disposal was fitted recently, check the blanking plug was knocked out of the spigot

Common questions

Why is my White Knight dishwasher not draining?

The cycle ends with dirty water standing in the bottom of the machine. A dishwasher drains through a filter, a pump, and then a hose that usually loops up and into the sink waste. Standing water almost always means a blockage in that path rather than a failed part — food debris in the filter and a blocked sink trap between them account for most of it. The one to check first is whether a new sink or waste disposal has been fitted, because the blanking plug in a new waste spigot is a classic.

Can I fix a White Knight dishwasher not draining myself?

Bail out the standing water, then lift out the filter assembly and clean it thoroughly. Check the sump underneath the filter for glass, labels and debris. Check the sink trap the dishwasher drains into — clearing that alone fixes a good share of these. If a sink or waste disposal was fitted recently, check the blanking plug was knocked out of the spigot. Those checks fix it more often than not.

What White Knight error codes mean not draining?

White Knight dishwashers report this through their own fault codes. The ones that point at not draining are F02, F04, F08. If your machine is showing one of those, that narrows it down considerably — each has its own guide on this site.

How much does a White Knight dishwasher repair cost?

£66 including VAT for an engineer to come out and diagnose it, or £84 in total including VAT if it is put right on the visit and no parts are needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Other White Knight dishwasher faults

• dishwasher will not switch on
• dishwasher not cleaning the dishes
• dishwasher not drying the dishes
• dishwasher leaking
• dishwasher not heating the water
• dishwasher lights flashing

Repairs we cover near you

• Dishwasher Repairs — what we charge and how it works
• Dishwasher Repairs in Nottingham
• Dishwasher Repairs in Arnold
• Dishwasher Repairs in Beeston
• Dishwasher Repairs in West Bridgford

Written by the engineers at ASAP Repairs from our own repair notes. See also our general guide to dishwashers not draining and our White Knight repairs page.