Never puncture, drill or probe anything behind the service flaps
Cleaning the filters and the exchanger surface through the designed openings is owner work. Anything beyond that is not. The tubing behind those panels is thin, it is under pressure, and damaging it releases refrigerant, ends the appliance's working life and creates a hazard. If a fin cleaner will not reach it, it is a technician's job.
What you find
- A hot or acrid smell during operation — Serious on any appliance, and a reason to isolate immediately.
- The breaker trips when the machine runs — Current going where it should not, and resetting is not a diagnosis.
- The room becomes very warm during a cycle — Expected to a degree; excessive means the space is too enclosed.
- Water on the floor under the machine — A condensate path problem, and water beside an appliance is its own hazard.
- Damaged or bent fins visible at the exchanger — A warning that something has been forced where it should not be.
- NEAR MISS: a warm cabinet and a long cycle — Normal for this machine type rather than a fault.
Ranked for a heat-pump machine
- An enclosed space with no ventilation — First. The appliance rejects heat into the room, and a sealed cupboard makes it run hotter and longer than intended.
- A blocked filter stage or exchanger — Second. It restricts airflow, raises temperatures, and is the maintenance item owners least expect.
- A condensate path that is leaking or blocked — Third. It puts water where an appliance and a socket are, which is a hazard as well as a nuisance.
- A supply connection problem — Last, and it is the same question as on any appliance: heat at the plug or the socket.
Ventilation, filters, water, supply
- Check the space the machine lives in and its clearances — The top cause and the one nobody checks.
- Clean both filter stages and the exchanger surface — It lowers running temperatures and improves everything.
- Check for water under or behind the machine — It is both a hazard and a sign of a blocked condensate path.
- Feel the plug and socket after a cycle — The ordinary supply check that applies to every appliance.
Owner steps
- Check the clearances the manual requires around the machine — Heat-pump machines reject heat into the room and need space to do it.
About 10 min
- Clean the door filter and the lower filter stage — Restricted airflow raises temperatures throughout the appliance.
Tools: gloves, warm waterAbout 20 min
- Clean the exchanger fins with a soft brush only — Nothing sharp and nothing forced; the tubing behind them is thin and under pressure.
Tools: brushAbout 20 min
- Check under and behind the machine for water and dry it — Water beside an energised appliance is a hazard regardless of where it came from.
Tools: towelsAbout 10 min
- STOP before any panel beyond the service flaps is opened or anything is prised — A sealed refrigerant circuit and mains wiring sit behind them, and neither is owner work.
The rules for a sealed system
Safety
Unplug the appliance or switch off its breaker before removing any panel, and never run the machine with a filter missing. Never puncture, drill, prise or probe anything behind the service flaps: the refrigerant circuit is sealed and under pressure. Do not run a dryer unattended overnight, and stop at once for any scorched smell or a breaker that trips.
When to call
Call immediately for a scorched smell, a breaker that trips, or any damage to the exchanger fins or tubing. Call for water appearing under the machine. Say that the appliance is a heat-pump model: the parts, the handling and the qualifications needed are different from a vented or condenser machine.
Nearest pages of this class
Scope of this page
Written for the Bosch dryer class rather than one model line, with heat-pump machines in mind because the sealed system is the distinctive factor. Required clearances and service flaps differ by family, and the manual is the authority for yours.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
