I have been to two w/bosch 24 sbi boilers working in parralel and both broke down at the same time after following the fault chart and a conversation with worcester help line it was decided the fans had gone. only being able to purchase 1 fan locally and fitting same made no improvement the pump works but the fan dosnt although there is power to it.

SOURCE: fault light flashing 1 flash per second

Prior to writing the above fault I had asked the owner to turn the boiler temp controller , for the heating side, down just a fraction . I was phoned this morning to tell me that the boiler had stayed on allnight with no fault light . After consulting with the plumber who fitted the system it appears that there might not be a room stat ,

SOURCE: Bosch boiler System

it means that the boiler wants to be serviced, the boiler will still work fine. Once the boiler has been servcied, there are a succession of buttons, that need to be pressed, to tell the boiler that it nhas been serviced. then 365days after it will do it again. Its there to prompt you, to get the boiler serviced

SOURCE: Worcester combi boiler losing pressure & water through o/flow

having the same problem and its a new bolier. thanks , adriano.

SOURCE: My worcester Combi boiler loses pressure over 24

check the tops of all your radiator valves for bypass if found, easy to repair best of luck

SOURCE: Worcester Bosch Highflow 400 Boiler - no hot water or heating

Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Hi, this is Worcester, Bosch Group

Although we don't currently offer live technical support online, our Technical Support department will be able to help. Their number is 0844 892 3366 - they're open 6 days a week and on average answer calls within 20 second. If you want to know more about our Technical Support department visit our website
http://www.worcester-bosch.co.uk/homeowner/customer-service/customer-technical-support

We look forward to helping you