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Installation principles for backflow valves

Correct installation of backflow preventers

Backwater valves seal off the pipe against both backwater and sewage runoff. If, as in this incorrect installation, drainage points above the backwater level are routed via a backflow stop, this will result in self-flooding in the event of backwater. Therefore, downpipes must always be connected in the direction of flow behind backflow stops.

Criteria for the installation of a backwater valve

Backwater valves can be used if all of the following criteria are met:

  • Drainage object has a gradient to the sewer
  • It must be possible to dispense with the use of the drainage point in the event of backwater
  • The rooms to be protected must be of subordinate use. A boiler room is not a room of subordinate use.
  • There is no risk to the health of residents in the event of flooding
  • Significant material assets are not endangered in the event of flooding
  • The circle of users must be small and a toilet must be available to them above the backflow level

If one of these criteria is not met, it is absolutely necessary to install a lifting unit.
Further information on ACO backflow valves can be found on our product page.