Customer Questions and Answers for Drain Pump by Bosch

Hello Tom, thank you for contacting APP, Some units may leave a small amount of water in the Sump Assembly and appear to have not completely drained out, this is normal as long as the amount left after the cycle only seems to be down in the Sump itself. If the unit is leaving an excessive amount of water in the tub there may be an issue with the Drain Pump 00631200, the Sump’s Check Valve 00611320, the Pump Filter 00645038, or the installation of the Drain Hose 00744881. If you are hearing the Drain Pump sometimes hum and not pull water out of the unit replace the Drain Pump. To test if the check valve has failed, and is allowing water back into the unit after being drained, remove the end of the Drain Hose from where it connects to home’s drainage system, lift it above the level of the unit, and fill the drain hose with water, if you begin seeing water flowing back into the tub the check valve has failed and will need to be replaced. Also, check that the Pump Filter in the top of the sump has not become blocked and verify that the Drain Hose is installed as per the manufacturer’s specifications.