The short answer
On the Ariston ARWDF dryer line, no heat is worth working through in a set order: a cycling thermostat or a thermistor cutting the heat first, then the heating element, or the igniter and gas valve coils, and only after those does the work that needs a meter or a teardown enter the picture. That order is written for a one-cabinet line and sequenced for how these models are put together, which is where it departs from the brand-generic article.
What you observe
- The machine heated intermittently before it stopped entirely — Intermittent heat that finally stops is the classic thermostat history.
- Everything else is normal and the exhaust stays cold — Cold exhaust with a clear vent and confirmed supply puts it in the heat source.
- NEAR MISS — there is heat but the clothes stay damp — That is airflow and sensing rather than heating; the cycle-fault page ranks those causes properly.
Causes, most likely first on the ARWDF line
- A cycling thermostat or a thermistor cutting the heat — Ranked first: the cycling thermostat is what turns the heat on and off during a normal cycle, and one that has failed open leaves a machine that tumbles and blows cold with nothing visibly wrong anywhere else.
- The heating element, or the igniter and gas valve coils — A failed element or igniter gives tumbling without heat, and which it is depends entirely on whether the machine is gas or electric.
- Half the electric supply is missing, or the gas is off — A missing supply leg or a closed gas valve leaves a machine that tumbles and never heats, which is the exact symptom here.
- A blocked vent that has opened the thermal fuse — The vent must be cleared whatever else is replaced, because a new fuse in a blocked machine opens again within days.
- High-limit safety devices, the control board or the gas valve — Last here, and the only cause on this list that is not owner work — high-limit thermostats, thermal cut-outs, boards and gas valves are all tested with a meter on live terminals, and on a gas machine that work sits next to the burner and its supply.
Check in this order, and why
- Ask whether the heat was intermittent before it failed — Intermittent heat points at a thermostat; a sudden total failure points at the element or the fuse. Done first because it separates the likeliest causes before any tool is needed.
- Confirm which fuel your machine uses at the data plate before anything else — Second: it confirms or dismisses what the first check suggested.
- Reset the double breaker fully, or confirm the gas supply valve is open — Third, once the two checks above are clean.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel — a capacitor can hold a charge after the power is off, and an electric dryer heat circuit is fed at a higher voltage than the rest of the machine. On a gas dryer, if you smell gas: do not switch anything on or off, leave the building, and call the gas utility or 911 from outside. Do not look for the leak yourself and do not disturb the burner or its supply line.
Models in the ARWDF family
Reference| Model number | Family key |
|---|---|
| ARWDF129(NA).1 | ariston:dryer:arwdf |
| ARWDF129S(NA).1 | ariston:dryer:arwdf |
When to call a technician
Call when the breaker has been fully reset, the vent is clear end to end and the exhaust is still cold, because what remains is the heat source and its safety circuit. Have the fuel type from the data plate ready.
Nearest pages of this class
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
