The short answer
On the WQG line, the most common reason a dryer is not heating is thermal fuse or high-limit thermostat open. On this page that cause is ranked ahead of half the electrical supply missing, which is where the order departs from the brand-generic article above; the ranking below says what about this platform moved it. Three of the four causes below are owner-checkable with no tools worth naming, and the last of them is a service call.
What you see on the WQG line
- Heat at the start of a cycle that fades — A thermostat or thermal cut-out opening on temperature behaves exactly like this.
- The outside of the cabinet running hot — Heat that stays inside the machine rather than leaving with the air points at restricted exhaust.
- Lint on the floor behind the machine — Escaping lint means a disconnected or split duct, which both wets the room and starves the airflow.
- NEAR MISS — it will not start at all — A dead machine belongs on the start page; this page assumes the drum turns.
Causes, most likely first on the WQG line
- Thermal fuse or high-limit thermostat open — The thermal fuse and the high-limit thermostat exist to open before a dryer becomes a fire. On many designs the fuse sits in the heat circuit only, so the drum turns perfectly and nothing gets warm. Replacing it without clearing the duct guarantees the same call again. Five models sit under this family key. They are close enough relatives that a fault found on one is worth suspecting on the others.
- Half the electrical supply missing — An electric dryer runs its motor on one leg and its heat on both. Lose one leg at the breaker or the cord and the machine tumbles happily and never heats — the single most misleading fault on this list. It is placed high because it imitates a failed heating element exactly while costing nothing at all to exclude.
- Blocked or restricted exhaust — A dryer does not dry by heating, it dries by moving heated air through cloth and carrying the moisture away. Take the airflow out and the machine bakes itself, opens a safety, and returns a wet load. It is the one cause that also destroys the parts below it.
- Moisture sensor or control board — A machine that trusts a filmed-over moisture sensor believes the load is dry before the heat has done anything. The cycle completes on schedule and the clothes are wet. It ranks last because it produces a partial failure rather than a total one, and because it needs a meter to separate it from the thermostats.
Check in this order, and why
- First: Look at the lint filter housing and the duct at the machine — Packed lint there is the evidence. Clear it before any part is ordered. It comes first because it is the cheapest of the four to exclude and because everything below it is harder to read while it is unresolved.
- Second: Reset the breaker fully off and on, and check the cord terminals — A dryer that tumbles but never heats with good safeties is a missing leg until proven otherwise.
- Third: Feel for airflow at the outside vent during a cycle — Weak or no flow at the flap is the answer. Disconnect the duct at the machine and run it briefly to compare.
- Last: Compare a timed cycle against an automatic one — Heat on timed but not on automatic points at the sensing side.
Before you open anything
Safety
Unplug the dryer or switch off its breaker before removing any panel — a capacitor can hold a charge after the power is off. Never bypass a thermal fuse, a high-limit thermostat or the door switch to get heat out of the machine: those parts open because the dryer is overheating, and defeating them is how a lint fire starts. If this is a gas machine and you smell gas, do not switch anything on or off — leave the building and call the gas utility or 911 from outside.
Models in the WQG family
Reference| Model number | Family key |
|---|---|
| WQG235D8AU | bosch:dryer:wqg |
| WQG235DRAU | bosch:dryer:wqg |
| WQG24200AU | bosch:dryer:wqg |
| WQG24201AU | bosch:dryer:wqg |
| WQG24203AU | bosch:dryer:wqg |
When to call a technician
Call once the vent is clear, the cycle is right and the breaker has been reset properly, because what remains — the element, the igniter, the thermostats — needs a meter on live terminals. Call at once on any burning smell, and do not restart the machine to confirm it.
