Basement laundry area with a top-load washer and dryer next to utility equipment
7 components covered

Field manual · Dryer

Bosch 300/500/800 compact 24-inch dryer (condensation and heat pump): field service manual

Covers: Bosch 24-inch compact ventless dryers sold in the US: 300 Series condensation (WTG86-series) and 500/800 Series heat-pump (WQB- and WTW-series). Series names only.

Single sourceBrands: Bosch7 components

Bosch compact dryers are ventless: a condensation model cools drum air in an air-to-air condenser, while heat-pump models use a refrigerant loop. Both collect water in a container or drain it through a hose. The condensation model is 240 V and ships with a power adapter that lets both the dryer and the matching Bosch washer plug into one standard 30 A dryer outlet.

Safety first

  • Unplug before service; 240 V tests are caution-level.
  • Heat-pump models: sealed system, refer to an EPA 608-certified technician.

How it works

Condensation (300 Series): drum air is pulled through the lint filter and then through a removable condenser where room air cools it so water drops out. Water is pumped to a container (with a full-tank indicator) or to a drain hose. Retailer specs list no self-cleaning condenser on this model, so the condenser must be cleaned by hand.

Heat pump (500/800 Series): the same air path, but a heat pump does the cooling and reheating. Bosch markets a self-cleaning condenser that uses water from the laundry to flush lint off the coil each cycle.

Power: the condensation model is listed at 208/240 V with a 3-prong NEMA 6-15 plug and about 10.5 A. Bosch supplies an adapter (WTZPA20UC) that plugs into a NEMA 14-30 dryer outlet and provides two 6-15 receptacles for the Bosch dryer and washer. The alternative is two separate 6-15/6-20 circuits.

Codes: Bosch regional support tables tie E01/E02 to a blocked fluff filter and E03 to a blocked or kinked condensate drain hose, with E06 and several higher numbers needing a technician. Confirm meanings on the US model's manual before quoting them.

Components & tests

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work. © 2026 OnCall Tech. Original content; not a reproduction of any manufacturer document.Generic part photos (not of this brand): Basement laundry area with a top-load washer and dryer next to utility equipment by Đỗ Huy Hoàng, Pexels License

Diagnostic guides for this appliance

Guide · Dryer

Ventless dryer not drying: cleaning the filters, condenser and heat exchanger

Ventless dryers depend on clean air passages. Lint that gets past the door filter settles on the condenser or heat exchanger and drying time climbs. Clean every filter stage first, then the condenser or exchanger, then check the water path.

8 steps ~40 mineasy
Guide · Dryer

Dryer squeaks, squeals or thumps: drum rollers, idler pulley, glides and rear bearing

Drum noise usually comes from four wear parts: the drum support rollers (thump, squeak), the idler pulley (squeal or whine), the front glides or bearing slides (scraping) and, on some designs, a rear drum bearing (squeal, drum moves front to back). Take the belt off and turn the drum by hand to find which one it is. Replace rollers as a set.

9 steps ~75 minmoderate
Guide · Dryer

Replacing a broken or slipping dryer drum belt

A broken belt leaves the motor spinning with no drum movement. Open the cabinet, put the new belt around the drum with the ribbed side against the drum, then route it through the idler and onto the motor pulley. Inspect the idler and rollers while you are in there.

7 steps ~50 minmoderate

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Miele T1 compact heat-pump dryers sold in the US (TWI180WP and related T1 WP models). Series names only.

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Whirlpool HybridCare heat-pump dryer (27-inch, ventless): field service manual

Whirlpool HybridCare full-size ventless heat-pump dryers (WHD-series, about 2015 onward). Series names only.

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Residential gas dryers with a hot-surface (glow-bar) igniter, a radiant flame sensor and a two-coil gas valve: Whirlpool-built 29-inch and GE-built gas dryers. Electrical diagnosis only.

7 components5 common failuresWhirlpool, Maytag, Kenmore, GE, Hotpoint
Bosch 300/500/800 compact 24-inch dryer (condensation and heat pump): field service manual · OnCall Tech