All unattended or Limited attended boilers must be inspected every three months by an approved maintenance contractor.  

Normally this contractor will have their own ISO 9001 certified management system.For an example of the requirements this can be found in the NZ approved code of practice for 'The Design, Safe Operation, Maintenance and Servicing of Boilers'.  We pride ourselves on ensuring that our client's boilers are operating within the code of practice and that all checks operate correctly.  We have also found that some companies with small boilers have taken it upon themselves to have their boilers checked by us to ensure continuous operation.