Urgent Ventilation advice needed please

If the boiler is located in an internal room/space that does not communicate directly with outside follow the following air ventilation requirement's: High level: 170 centimetre's square Low level: 340 centimetre's square If the boiler is located in a room/space that has a suitable external wall that communicates directly with the outside then follow the following air ventilation requirement's: High level: 85 centimetre's square Low level: 170 centimetre's square NB: Both the above air ventilation requirement's must be adhered to obviously if the boiler is within an internal room/space that does not communicate directly with atmosphere/outside also the air vents must be of a type that are NON-CLOSABLE AND FREE FROM ANY OBSTRUCTIONS AT ALL TIMES, such as furniture/book cases/shelving etc MOST IMPORTANT! Strongly recommend that you fit a CO detector too near the boiler, follow the CO manufactures instructions when installing it! Please ignore the post below regarding, ventilation requirements, As you mentioned a boiler in a compartment or cupboard, there is no specific criteria that predefines the size/volume of a 'compartment' so data given above is from the manufacturers own specifications within there boiler installation manual. Please do not deviate!

If the boiler is in a room with an external wall (not in a compartment) you need only a low ventilation. You say you have the manual, the manufacturer tells you how big it has to be. For your boiler it should be about 65 cm2 of FREE ventilation (never ever cover the ventilation: you need the draft). It is very important for an open flue boiler (as yours) to be serviced once a year, and is good practice to have a carbon monoxide alarm as well.