The short answer
On a vented machine the first question is not whether the heat source has failed but whether the machine could get rid of its heat at all. Ranked first on this platform: A blocked vent tripping the thermal protection. The checks below follow that ranking, and the first of them need no tools and no panel removed.
What you observe
- It heats for the first few minutes and then stops heating — Heat that stops part way through is a thermal protection opening.
- The heat stopped abruptly and permanently, often after a load that took unusually long — An abrupt permanent stop after a slow load is the fuse doing its job.
- The drum turns and the panel works but there has never been a trace of heat — Full mechanical operation with zero heat is the classic half-supply picture.
- NEAR MISS — the machine will not start at all — No drum rotation is a different chain entirely: door, start switch and supply.
Causes, most likely first on this platform
- A blocked vent tripping the thermal protection — A restricted duct makes the machine overheat, and overheating opens a thermal cut-out. It ranks first on this platform because a restricted duct makes the machine overheat and open a thermal cut-out, and on this platform that cut-out kills the heat while leaving the drum turning — which presents as a heating failure when it is the protection working exactly as intended.
- A thermal fuse that has opened — A thermal fuse is a one-shot device that opens permanently when the machine overheats. It ranks second here because the dryer is a vented machine with a belt-driven drum turning on felt seals and plastic glides, every one of which is a consumable part.
- Half the supply on a two-pole circuit — An electric dryer runs its motor from one side of its supply and its element from both. It ranks third rather than higher: real on this platform, and less common than the causes above it.
- The heating element or the gas igniter — On an electric machine the element is a coil that eventually breaks; on a gas machine the igniter weakens until it no longer gets the flame sensor to open the valve. It comes fourth in the order — a genuine cause here, behind the ones above it on frequency alone.
Check in this order, and why
- Feel the airflow at the outside vent hood a few minutes into a cycle — Weak flow outside plus lost heat is the diagnosis. It leads because it tests the top-ranked cause.
- Ask what the machine was doing in the load before the heat stopped — The history identifies this better than any inspection. Tests the second-ranked cause.
- Switch the double breaker fully off and back on again — One trip of a double pole can leave the machine exactly like this. Tests the third-ranked cause.
What an owner can safely check
- Disconnect and clear the whole duct run and check the outside flap — Do the whole run, not just the end you can reach.
Tools: screwdriver, vacuumAbout 30 min
- Reset the breaker fully off then on, and check the outlet if the machine is on a cord — If the breaker will not hold, stop and call.
About 10 min
- STOP at the first panel that needs a tool, and write up what you found — A technician who arrives knowing which checks came back clean spends the visit fixing rather than repeating them.
Before you open anything
Safety
Unplug the dryer or switch off its breaker before removing any panel.
When to call a technician
Call once the vent, the filter and the cycle selection have been eliminated, because what is left is an element, an igniter, a thermal cut-out or half a supply, and all four are measured rather than looked at. Call without waiting if there is any smell of scorching, or if the cabinet has been hot to the touch.
Nearest pages of this class
What this page does not cover
This page is written for the Moffat dryer as a class, not for one family or one model line. Where a family- or model-specific page exists for your unit, that page is the more specific answer and the one to read first. Deliberately not here: part numbers, wiring colours and disassembly order, which differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
