The error code E2 on a water cooler typically indicates a problem with the water flow. This could be due to a clogged filter, a broken pump, or a leak in the tubing. If you are seeing the error code E2, you should first check the filter to make sure it is clean and free of debris. If the filter is clean, then the next step is to check the pump. You can do this by listening for any unusual noises or vibrations coming from the pump. If the pump is not working properly, you will need to replace it. Finally, you should check for leaks in the tubing. This is a common problem with older water coolers, and it can be caused by wear and tear or by damage to the tubing. If you find a leak, you will need to repair or replace the tubing.