The most common reason is that the spray arm is being blocked by the load. Please always make sure that the spray arms can rotate freely after you have loaded the machine. You can do this by moving the spray arms mechanically yourself.
* Wash spray arms need to be regularly checked to ensure that the jets (small openings) are not blocked by food or debris. If blocked, remove, clean & replace. Once replaced, ensure that they spin freely.
* The centre post area, where wash arms sit, needs to be cleaned to remove debris.
* Make sure wash arms are secured and not loose.
* Blocked wash pump.