The short answer
On a Costway dishwasher, the distinction between a breaker tripping and a residual-current device tripping is the whole first half of the diagnosis: one is overload, the other is current leaking to earth. Note which one went before you touch anything else. Read the near-miss line in the symptoms first if you are not sure you are on the right page.
Signs, including the misleading ones
- The residual-current device trips rather than the breaker — Current is leaking to earth rather than the circuit being overloaded, which usually means water or insulation. Mention it when you book a visit; it changes which parts a technician brings.
- Heat marks or browning at the plug or connection — A poor connection heating under load, which is a fault in its own right regardless of the machine. If you can only do one check, make it this one.
- Water under the machine as well as a trip — The two usually travel together, and the water is normally the cause rather than the coincidence. Write it down before anybody comes out; a described symptom is worth more than a remembered one.
- Tripping only when the machine drains — That timing points at the drain pump rather than the heater. Do this before the check below it, because the answer changes what that one means.
The ranking
- Water reaching a terminal, connector or the motor — A built-in machine leaks into its own cabinet unseen, and the electrical symptom is often the first visible sign. This is the cause people skip, and skipping it is why the diagnosis takes three visits.
- A damaged supply cord or a poor connection — Crushing when the machine was pushed into its housing and heat at the connection both produce trips and smells. That single observation eliminates more of the list than any amount of guessing.
- A failing drain or wash pump — A motor breaking down draws more than it should, and a stalled one draws a great deal more. It belongs in the order here because the check for it is cheap and the answer is unambiguous.
- A shared or undersized circuit — An installation fault rather than an appliance one, but the symptom at the consumer unit is identical. Keep an eye on whether it is getting worse, because the rate of change is itself evidence.
Where to start, and why there
- Note which device tripped and at what moment — Breaker or residual-current device, and how far into the cycle: those two facts are half the diagnosis. The value is in eliminating, not confirming; most of these come back negative and that is useful.
- Look under and behind the machine for water — A built-in appliance hides its leaks, so look at the floor of the housing rather than just the kitchen floor. Eliminate it properly before moving down; a half-checked cause comes back later.
- Check whether anything else shares the circuit — A circuit already near its limit trips without any appliance being faulty. Do it with the machine in its normal state rather than after you have already changed something.
Owner steps, in order
- Switch off at the breaker and leave the machine isolated — Do not reset repeatedly to see what happens; that is the one action that makes a bad fault worse. Keep the parts you remove in the order you removed them.
About 5 min
- Close the water supply to the machine — If water is part of the picture, taking the pressure off stops it getting worse while you wait. Do this before the check below it, because the answer changes what that one means.
About 10 min
- Write down the exact circumstances of the trip — Programme, elapsed time, which device tripped, and anything you could smell. This is safe owner work as long as the power is genuinely off.
About 10 min
- Stop at this point: what follows needs a meter on a live circuit — Past this point the checks need test gear and the training to use it safely.
Read this before touching it
Safety
Pull the plug before anything else; a wall switch is not proof the appliance is dead. Treat the wiring as live until you have proved otherwise, whatever the switch says. Dry the floor before you kneel, and keep towels between you and any puddle. Nothing here asks you to interfere with a switch that senses the door, and nothing should.
When to call a technician
Here is the split as a technician would put it. Isolating, closing the water and looking for the leak are yours; the element, the pumps, the harness and the earth path are not. It is drawn where the next step stops being reversible. Call promptly if water has reached the floor more than once, since a leak that returns has usually found a path you cannot see.
Related pages of the same kind
What is deliberately not here
Generalized information, stated plainly: this is written across Costway dishwasher families.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
