You can tell from a various perspectives of which component might be faulty. The end wash result will tell you more about the condition of the dishwasher, if could be the sprays if your dishes are dirtier, it could be the water heater and may be spraying only cold water. Various factors contribute to this. If you cannot understand the technical details of the dishwasher then we recommend you leave the job to experts. Our expert technicians will inform you about the problem and its solution.