Auditors working for the Department for the Economy (DfE) are inspecting five businesses each week that have Renewable Heat Incentive (RHI) accredited boilers.On enquiry, a DfE spokesperson said 73 sites containing 223 boilers have been audited in the latest phase of the programme, which began in the summer. A pilot audit scheme last year saw 33 sites audited. There are 1,270 sites with RHI boilers in NI.