Back-Flow Preventer Repairs & Complete Rebuilds

Why Backflow Preventers Fail

Common causes include:

• Debris inside check valves
• Worn rubber discs
• Damaged O-rings
• Weak or broken springs
• Corrosion
• Freeze damage
• Relief-valve wear
• Failed shutoff valves

Water quality and system pressure can also influence wear.

Repair vs. Complete Rebuild

A targeted repair addresses the specific failed component. For example, one leaking check valve may require cleaning or replacement of internal parts. A complete rebuild may be more appropriate when several wear components have deteriorated.

The decision should consider:

• Age of the assembly
• Failure history
• Cost of parts
• Internal condition
• Availability of rebuild kits
• Replacement cost

A successful backflow repair should restore measurable device performance, not simply stop visible leakage.

That is why testing after repair is important.

RP Backflow Preventer Repairs

Reduced Pressure Principle assemblies contain two check valves and a relief-valve zone. Common problems include continuous discharge, leaking checks, and inability to maintain required pressure relationships. Repairs may involve replacing check components, relief-valve parts, seals, or springs.

DC and DCDA Rebuilds

Double Check assemblies rely on two independently operating checks. DCDA assemblies add bypass or detector components and are frequently used in fire protection systems. Failures may involve check components, shutoff valves, or bypass parts.

Vacuum Breaker Repair

Vacuum breakers are designed to prevent backsiphonage in specific applications. Worn seals or damaged internal parts may cause leakage or test failure. Depending on the design, repairs may be relatively simple or replacement may be more practical.

When Replacement Makes More Sense

Replacement may be preferable when:

• The body is cracked
• Corrosion is severe
• Parts are obsolete
• The device is improperly sized
• Repair cost approaches replacement cost
• Repeated rebuilds are no longer economical
• Testing After Repair

After internal components are serviced, the assembly should be retested when applicable. This confirms that check valves and relief components now meet required operating criteria.

Extending Equipment Life

Routine testing can identify problems before they develop into complete failure.

Protecting the assembly from weather, freezing, impact, and unauthorized access can also extend service life.

A professional rebuild can be an effective way to return an otherwise serviceable backflow preventer to proper operation while avoiding unnecessary replacement of the entire assembly.