I am just about to mount a new boiler Worcester Greenstar 30i in a small storage area. I want to maximise available space but keep reasonable access to the boiler for future maintenance. How much side clearance is recommended to give good access, and is there one side more important than the other ? the manual just states minimum of 5cm.
Let your Gas Safe registered installer install it correctly for you, and dont you try to DIY with a gas appliance. That way you can be certain it has been installed to manufacturers instructions and will not be a danger to you and your family.
Installation of the boiler including gas is already arranged with a registered gas fitter, I am only installing the piping chasis and have a choice of where it goes on the wall.