Bosch, a German company, produces consumer appliances that are sold around the world. It produced the Classixx series, which is an older series of dishwashers only sold in the United Kingdom. A common problem with these dishwashers is that they sometimes don't drain properly. You can often easily fix this problem, saving yourself money on service fees.
Pump/Water Level Control
The dishwasher pump is responsible for moving water out of the tub. The pump can get clogged with debris, which you can clean out with a toothpick. Remove the bottom rack and spray arm to access the pump. If the pump looks clean, see if any component is broken. The impeller inside the pump often breaks. You usually cannot fix this component, which means that you must replace the whole assembly. Check the water level assembly, which is located under a metal panel on the left side of the dishwasher. Clean the assembly if dirty.
Your Bosch Classixx dishwasher often won't drain due to a kink in the drain line. Straighten the line, or replace it if it's badly crushed. Disconnect the dishwasher from the power supply, and remove the drain line. Look inside it with a flashlight, and dig out any clogs with a plastic spoon. If you have an air gap installed, clean it out. The air gap is located near the sink. If you don't have an air gap, install a high drain loop. Attach the drain line to the base of the countertop and create a loop. This prevents water from the sink from flowing into the tub.
Check Valve/Household Plumbing
The check valve is responsible for preventing water exiting the dishwasher from moving back into the tub. The valve is located near the pump assembly. Examine the valve, and see if anything is preventing it from opening and closing. Clean it out. If the valve is stuck open or closed, order a new one from a Bosch authorised parts dealer. Verify that your household plumbing is draining properly. If not, clean it out with plumbing tools or cleaning products.
If you haven't used your Bosch Classixx dishwasher in a while, disconnect the dishwasher from power source, and check the motor. Oftentimes, the motor sticks if you haven't used it for a while. Turn the motor until it freely rotates. If it won't turn, you must order a new motor from a Bosch parts dealer since this component is difficult to fix.