The short answer
When a DHP dryer tumbles cold, the first question is not what failed but why the protection opened. Answer that and the repair holds; skip it and the same part fails again within weeks.
What you observe
- Drum turns normally but the air is cold — Everything mechanical is fine and the heat circuit is open somewhere.
- It heated until recently and stopped suddenly — A sudden loss points at a protection device rather than at gradual wear.
- Weak heat rather than none at all — Points at a thermostat or a partial element fault rather than an open protection device.
- Heat for a few minutes then nothing — A device opening as the machine warms, which is again an airflow signature.
- NEAR MISS - the drum does not turn at all — That is a no-start or belt fault and belongs on the start page.
Causes, most likely first on DHP
- Heating element or its circuit — Ranked first on the DHP family: a large appliance circuit is typically 30 A or higher at 240 V, so a machine that has lost one leg tumbles perfectly and makes no heat at all. These codes share a drum, a blower and a heater arrangement, so a finding on one is worth assuming on the rest. This moves above restricted or blocked exhaust duct, which leads the brand-generic order, because these models share one layout, so its weak point shows across the whole family.
- Thermal fuse or high-limit device open — Second: these devices are one-shot on this platform, so they explain a sudden total loss of heat rather than a gradual fade.
- Restricted or blocked exhaust duct — Third: the duct is the condition rather than the part: restrict it and the protection chain opens, which is why clearing it is the repair and not the preparation for one.
- Control board or the heat relay — Fourth: last, because between the duct, the protection chain and the supply there is very little left for a board to explain.
- Cycling thermostat or thermistor — Last: a drifted control sensor gives weak heat rather than none, so it sits below the one-shot devices in this order.
Check in this order, and why
- Disconnect and inspect the whole exhaust duct — Do this first: it is both the commonest cause and the condition that destroyed whatever part failed.
- Confirm the machine still tumbles and the timer advances — It separates a heat-circuit fault from a wider electrical fault.
- Check the outside vent hood opens and is clear — A flap held shut by lint restricts the run even when the duct itself is clean.
- Have the supply checked if the machine runs on two legs — Losing one leg leaves the motor running and the heat dead, which is exactly this symptom.
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. Treat lint as the fire hazard it is: clear it out of the filter housing and the duct rather than pushing it further in, and run the machine only with its panels fitted and its duct connected to the outside.
When to call a technician
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Clearing the duct is owner work and is the part that matters. Call for anything inside the cabinet: the protection devices sit next to the heater and are tested live.
Other DHP pages
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
