Bosch Fan 87072040380

The Bosch Fan 87072040380 is a spare part designed for Bosch Gaz 3000/4000 OW/ZS/ZW/WT gas boilers. It operates at 50 W, providing combustion air to the burner and, in sealed appliances, expelling flue gases. This fan is essential for maintaining proper air-fuel mixture and preventing overheating. Its construction ensures efficient cooling and straightforward installation.

When selecting a replacement fan of this type, verify the required air flow and pressure at the burner's rated output, outlet direction and orientation, impeller diameter, supply voltage, and control interface (mains on/off, PWM, or 0-10 V). The flange pattern must match the boiler housing. Ensure the new fan's electrical ratings and control signal type are compatible with the original, and check that pressure tap points align with the air pressure switch.

Common failures include worn bearings causing noise or rotor seizure, imbalance from dust or debris on the impeller, failed start/run capacitors, and speed feedback errors that trigger a lockout as an airflow fault. Symptoms may include unusual noises, reduced heating performance, or boiler shutdown. Inspect the fan for bearing wear, debris buildup, and capacitor condition, and verify speed sensor operation.