Ferroli 39842120 Compatible Diverter Valve- Ferroli i series Ferroli 39842120 Compatible Diverter valve – Ferroli i series Keep your heating running smoothly with this compatible replacement boiler part. Part number: 39842120. Designed for dependable performance, it’s ideal for boiler repairs, servicing and maintenance. Why buy this part: ✓ Reliable compatible alternative ✓ Helps restore efficient boiler operation ✓ Suitable for professional repair & maintenance ⚠️ We recommend that all parts are fitted by a fully qualified gas safe certified technician.