What to check yourself
Step 1. Cut the power for five minutes
First, because a single bad reading can latch this and a reset tells you whether that is all it was. If it comes straight back on the next cycle, the fault is real.
Step 2. Measure what is coming in from the tap
Free, quick, and it catches a real cause. A dishwasher plumbed into the hot line takes whatever the water heater sends. A heater set high, around 140°F or above, can push the machine past its limit before it has heated anything itself. A cooking thermometer under the kitchen hot tap answers it.
Water above 120°F scalds quickly. Fill a cup and measure that rather than holding a hand under the tap.
Step 3. Note when in the cycle it appears
Early, during the main wash, or in the dry? Say which when you call. Overheating during drying points at the element circuit staying on, early overheating points at the supply or the sensor, and it saves a chunk of diagnosis time.
What a technician will look at
Described so you know what you are paying for, not as steps to repeat.
Test the thermistor, the element and the relay on the board
Three parts produce this: a sensor reading low so the machine keeps heating, an element that will not switch off, or a relay on the board welded closed. Only a meter tells them apart, and the last one is the reason not to keep running the machine in the meantime.
When to call a technician
If it returns after a reset, and before running anything else. Heating that will not stop is the one dishwasher fault where waiting has a real downside, and a welded relay does not repair itself.
What the repair costs
| Repair | Part only | Fitted by a technician |
|---|---|---|
| Turning the water heater down, if the supply was too hot | - | Free |
| Diagnosis alone | - | $75 to $130 |
| Temperature sensor replacement | $15 to $60 | $150 to $300 |
| Heating element replacement | $25 to $75 | $200 to $350 |
| Control board replacement | - | $300 to $550 |
A new machine of the same class runs $500 to $1,500. Once a quote passes about a third of that on an older appliance, the repair stops making sense.
Codes people confuse this with
Questions people ask
- What is the difference between HC and HE?
- Opposite directions. HC means the water got too hot. HE means it never got hot enough. The parts overlap, the sensor and the element and the board, but the failure is the other way round and so is the urgency: HE can wait, HC should not.
- Should I turn my water heater down?
- If the kitchen hot tap runs above about 140°F, yes, and it is worth doing anyway. Most homes are fine at 120°F, which is also the temperature most dishwashers are designed around.
- My Whirlpool washer showed HC too. Is it the same fault?
- No. On a Whirlpool washing machine HC means the hot and cold hoses are connected the wrong way round. Same two letters, different manufacturer, unrelated problem.
Which machines this applies to
Applies to
Samsung dishwashers across the DW80, DW50 and Linear Wash ranges. Independent sources put the trip point around 176°F.
Last checked
2026-08-10