Leaks are to be classed as annoying they can appear anywhere on the coil. The reason for the leak may not be apparent in the initial stages. This must be determined prior to repairing the leak.
Some leaks are caused by corrosion, pipework freezing up, mechanical damage, neglect or overpressure.
These causes need to be addressed If not the fault will reappear again, maybe not in the same area but it will reappear. In some cases further works may be required. If the leak is in the Matrix then other works will be explained as to rectify the fault.
In some cases On-Site repair may not be an option. The coil can be investigated and repaired at out Factory.