What Are Sump Locks on a Dishwasher?

Sump Motor

• The motor of a dishwasher is the strongest part of the appliance. Its entire purpose is to suck dirty water out of the bottom of the dishwasher through the bottom particle filter and to push it through the sink’s plumbing into the drain. If a dishwasher is not draining or you hear strange noises, there is most likely a clog in the sump line, and the motor is having difficulty doing its job.

Sump Timer Switch

• The sump pump and the sump locks must work together to prevent a backwash of dirty water into the dishwasher. The way this happens is through the sump timer switch, which is a component inside the timer that sends an electrical signal to the motor each time it needs to pump water. Without this signal, the sump motor will not run.

Sump Locks

• The sump locks are small valves located inside the sump tubing. The valves are activated by pressure and will remain closed so long as there is adequate pressure on the sink side of the connection. If there is insufficient pressure, the sump locks cannot function, and there will be a backwash of water and sewage smells in the dishwasher.

Sump Tubing

• When properly installed, the sump tubing goes into a kitchen cabinet and is positioned higher than the S-bend in the sink tubing. This is necessary to provide enough pressure for the sump lock to close. If you open the cabinet and see a black buildup in the sump tubing, it means that the tubing is not placed high enough.