Emergency Back-Flow Repairs (RP, DC, DCDA & Vacuum Breakers)

Types of Backflow Preventers

Common assemblies include:

• Reduced Pressure Principle assemblies (RP)
• Double Check assemblies (DC)
• Double Check Detector Assemblies (DCDA)
• Vacuum breakers

Each type is designed for different applications and levels of protection.

The correct repair procedure depends on the specific device.

Common Emergency Backflow Problems

Backflow assemblies can experience:

• Continuous relief-valve discharge
• Failed check valves
• Leaking shutoff valves
• Broken test cocks
• Cracked bodies
• Freeze damage
• Damaged internal springs
• Failed seals
• Loss of downstream water service

Some symptoms are dramatic, particularly when an RP assembly releases a large amount of water.

Why an RP Backflow Device May Discharge

Reduced Pressure Principle assemblies include a relief valve that is intended to open under certain hydraulic conditions. Continuous discharge may indicate a failed check valve, debris, worn internal components, or pressure-related problems. The relief opening should never simply be blocked to stop the water. A backflow preventer should not be bypassed or disabled simply because it is leaking; the device exists to protect the potable water system.

Emergency Repair Process

Depending on the assembly, repair may involve:

• Testing the device
• Disassembling internal checks
• Removing debris
• Replacing seals or springs
• Repairing relief components
• Replacing damaged shutoff valves
• Retesting after repair

If the device body is cracked or severely corroded, complete replacement may be more practical than rebuilding.

RP, DC and DCDA Repairs

RP assemblies contain multiple internal components and a relief zone.

DC assemblies use two independently operating checks.

DCDA assemblies are commonly associated with fire protection systems and may include bypass components.

Each device should be diagnosed based on measured performance rather than visual appearance alone.

Vacuum Breaker Repairs

Vacuum breakers are used to prevent backsiphonage in specific applications. Leaks or failures can result from worn internal components, debris, or damaged seals. Repair suitability depends on the device type and condition.

Testing After Emergency Repair

After the repair, the assembly should be tested when applicable to verify that internal components are functioning correctly. Certification or documentation may be required depending on the local authority and application.

Preventing Future Emergencies

Regular testing and maintenance can identify deteriorating components before the device fails completely. Protective enclosures and freeze protection may also reduce damage to exposed equipment. Emergency backflow repair is successful only when two objectives are achieved: normal water service is restored and the assembly continues protecting the potable water system as intended.