An iced-up evaporator is a common service call for any service technician working in this industry. Generally, determining this is the cause of the system problem is rather easy. But what caused the evaporator to ice up may not always be obvious.
Troubleshooting an iced evaporator should begin with a visual inspection of the coil and its icing pattern. This may not always be easy, as some cabinets or enclosures can make it hard to inspect. In other cases, the evaporator is mounted high up in the case, making it difficult to see. But, a technician should take the extra time to inspect the coil, as it will help him or her determine the true cause of the problem.