How Often Should a Worcester Bosch Boiler Be Serviced? A Worcester Bosch boiler should be serviced once every 12 months. Under section 4.2 of Worcester Bosch warranty terms, missing this annual check invalidates your 5 to 12-year manufacturer guarantee. Servicing is a strict condition of ongoing cover rather than an optional recommendation. For rental properties, … Continue reading How Often Should a Worcester Bosch Boiler Be Serviced?