Water not getting hot
A dishwasher isn't getting water from your water heater and washing with it directly — it's heating the water further in the tub. The household hot tap supplies water at whatever temperature your water heater produces (typically 110-125°F), and the dishwasher's own heating element in the sump raises it further to 120-150°F for the main wash or up to 160°F for sanitize cycles. This distinction matters: if wash water is cold or lukewarm, the problem is usually the dishwasher's heating element or its temperature sensor, not the water heater. A failed heating element also explains wet dishes, because the same element that heats wash water also powers the heated-dry phase. On the other hand, incoming water starting colder than 110°F can defeat an otherwise healthy heater on short cycles, because short cycles don't run the heater long enough to recover. Diagnose starting with the heating element itself, then work outward to sensors and incoming temperature.
Safety
Critical- Kill the breaker before heating element work: Dishwasher heating elements run at 120V and their terminals sit exposed beneath the tub. Always turn off the dishwasher's dedicated breaker before removing the kick plate or touching the element terminals. A non-contact voltage tester should confirm power is off before reaching in.
- A shorted element can energize the tub: When a heating element's sheathing fails, the element can short to the grounded tub chassis. This can create a shock hazard on the tub surface and usually trips the dishwasher's GFCI or breaker. If you feel a tingle on the tub or the breaker trips repeatedly when the dishwasher runs, kill the breaker and do not use the dishwasher until the element is replaced.
- Element stays hot after cycle: The heating element can remain at 160°F or hotter for 15-20 minutes after a cycle ends, especially after a sanitize cycle. Allow full cooldown before touching the element or reaching into the sump. Burns from the element are uncommon because of its recessed location, but possible during repairs.
- Plastic items can deform near the element: Plastic bowls, containers, and utensils that contact the heating element during a cycle can soften and melt onto the element surface. Keep plastic on the top rack. If plastic has melted onto the element, let the dishwasher cool completely before attempting to scrape the residue off, and avoid running the element until clean.
How to approach this
Pause the dishwasher about 15 minutes into the main wash and touch the inside of the door. It should be uncomfortably warm to hot — around 130-140°F. Cool or lukewarm water means heating isn't happening. Next, locate the heating element — a metal loop along the bottom of the tub — and inspect for visible damage: a break in the coil, a bubbled or scorched section, or discoloration. Turn off the breaker and test continuity across the element's terminals (accessed behind the lower kick plate). A working element reads 10-30 ohms; infinite ohms means it's failed open. If the element tests fine, check the incoming water temperature at the kitchen sink hot tap before starting a cycle — water below 110°F at the tap means the dishwasher can't reasonably heat to main-wash temperature within a short cycle. Finally, if the element is intact and incoming water is hot, the thermistor may be drifted — it can report higher temperatures than reality, causing the control to cut the heating early.
Common causes
Ordered by how frequently each component is involved, based on OEM manual analysis.
Failed heating element
Most commonThe heating element is a metal loop along the bottom of the tub that both heats wash water and powers the heated-dry phase. It fails open (circuit breaks from repeated thermal cycling) or fails grounded (sheathing wears through, shorting to the tub chassis). A failed element produces cold wash water, wet dishes, and on shorted cases, a tripped breaker. Replacement elements run $40-100 and take 30-60 minutes with the dishwasher tipped on its back.
Low incoming water temperature
CommonDishwashers expect incoming hot water around 120°F. If your water heater is set lower (energy-saver presets are often 110-115°F) or if the run from water heater to dishwasher is long, incoming water can start in the 90s. The heating element needs to raise temperature to main-wash spec, which it can do — but short cycles don't run the heater long enough to fully recover. Flush the kitchen hot tap before starting a cycle.
Thermistor drift or failure
CommonThe thermistor reports water temperature to the control board. If the sensor drifts out of calibration (common with age and thermal cycling) or fails electrically, the board reads incorrect temperature and can cut the heating cycle before the water is actually hot enough. Diagnose by checking thermistor resistance against the manufacturer's spec at a known reference temperature — deviation over 10% warrants replacement. Thermistors run $20-40.
Short cycle selected
CommonQuick, express, or light wash cycles run 30-60 minutes and don't allow the heating element time to fully heat wash water and maintain temperature. Cold-starting water on a short cycle often finishes the wash phase at only 100-110°F, below what detergent enzymes need to activate fully. If dishes come out partially clean on quick cycles but fully clean on normal cycles, the dishwasher is heating normally — the cycle time is just too short to reach temperature.
Failed high-limit thermostat
Less commonMost dishwashers have a safety thermostat that cuts power to the heating element if water temperature exceeds a safe maximum (typically 180°F). If the high-limit trips prematurely — from a failing component or a debris-clogged sump causing localized heat — the element stops heating before reaching wash temperature. Symptoms are erratic heating: some cycles get hot, others don't. Testing requires confirming the thermostat's reset trigger and often replacing the part if it trips repeatedly.
Parts commonly needed
No verified parts are currently associated with this symptom for the DDW24T998US.
View all parts for this modelStill narrowing things down?
Seeing an error code on your display? Look up your error code → for more specific diagnostic information.
How we verify parts for your model. Parts shown are confirmed at multiple retailers specifically for the DDW24T998US. Cross-referenced against OEM documentation.
About this content. Common causes and FAQs are generated from OEM manual analysis and verified parts data. This is general guidance - your specific model may have different components or access points. Always verify with your model's documentation before ordering parts.