How to Troubleshoot Watts Backflow Preventers

When troubleshooting Watts backflow preventers, we'll first determine whether it's an ASSE 1013 (RP) or 1015 (DC) model. For leaking relief valves, open a downstream fixture to create pressure differential and check if the dripping stops. Most failures (90-95%) occur in the first check valve, so inspect for debris or improper o-ring placement. Installing upstream strainers and performing quarterly maintenance prevents most common issues before they become costly emergencies.

Key Takeaways

• Check if the relief valve is leaking by opening a downstream fixture to create a pressure differential.
• Inspect the first check valve for debris since it accounts for 90-95% of backflow preventer failures.
• Look for incorrectly positioned O-rings that may occur after reassembly and cause persistent leaks.
• Install upstream strainers to capture 99% of debris before it enters the backflow preventer system.
• Conduct quarterly maintenance including check valve cleaning to prevent system breakdowns.

Understanding ASSE 1013 vs. ASSE 1015 Device Functionality

When troubleshooting backflow preventers, understanding the fundamental differences between ASSE 1013 and ASSE 1015 devices is essential for proper maintenance and operation.

ASSE 1013 (RP) devices protect against health hazards using two check valves plus a relief valve, requiring a minimum 12-pound pressure differential to function correctly. When this pressure drops, the relief valve activates to prevent potential contamination.

In contrast, ASSE 1015 (DC) devices tackle non-health hazards like taste and odor problems using only two check valves, needing just 1 pound of pressure across each valve. Without a relief valve, they can't respond to significant backpressure situations.

Both types commonly fail due to debris accumulation in the check valves.

That's why we recommend quarterly inspections and cleanings, along with regular performance testing to catch issues that might develop months after installation.

Common Failure Points and Their Root Causes

Understanding backflow prevention isn't complete without examining what actually goes wrong with these devices in real-world situations.

In our experience, the first check valve is the primary culprit, accounting for 90-95% of failures due to debris disrupting pressure equalization. The second check valve fails less frequently (about 5% of cases) but can still degrade from dirt accumulation or wear.

First check valves cause 90-95% of backflow failures, while second check valves account for only 5% of issues.

Relief valve malfunctions typically stem from debris buildup or improper reassembly after maintenance, causing anything from intermittent leaks to constant dripping.

We've also seen pressure differential issues emerge months after installation when proper startup procedures weren't followed—a common problem with ASSE 1013 devices.

Don't underestimate the importance of regular inspections and cleaning.

We've witnessed how neglected maintenance leads to system breakdowns that could have been prevented with routine care.

Step-by-Step Relief Valve Troubleshooting Procedure

A reliable relief valve is the heart of your backflow preventer, and when it starts dripping, you need a systematic approach to identify the culprit.

Let's walk through the process together.

First, open a downstream fixture or test #4 valve to create pressure differential. If dripping stops when you close the second check valve, you've found your issue—the second check valve likely needs inspection for failures.

Next, examine for debris or dirt, the most common troublemakers. These tiny invaders frequently cause relief valve malfunctions and are easily missed during casual inspections.

Don't overlook proper assembly—incorrectly positioned o-rings or reassembly errors often lead to intermittent dripping.

We recommend implementing quarterly maintenance schedules to keep your system in peak condition and prevent minor issues from becoming major headaches.

Preventive Maintenance Strategies for Extended Service Life

The lifespan of your backflow preventer can double or even triple with the right preventive maintenance approach. We've found that quarterly inspections are non-negotiable for keeping Watts devices operating reliably. Installing upstream strainers is a game-changer, capturing nearly all debris before it can cause damage.

Remember to follow manufacturer guidelines during startup procedures—this maintains proper pressure differentials critical for ASSE 1013 devices. We've seen consistent maintenance virtually eliminate emergency calls while dramatically extending system life. Your detailed maintenance records become invaluable diagnostic tools when troubleshooting becomes necessary.

Frequently Asked Questions

How to Tell if a Backflow Preventer Is Bad?

We'll know our backflow preventer is failing if we see consistent dripping from the relief valve, experience pressure drops below 12 pounds, or notice leaks only when downstream pressure decreases.

How Do I Test My Backflow Preventer?

We'll test your backflow preventer by checking for leaks at the relief valve, measuring pressure differentials (12 pounds for ASSE 1013, 1 pound for ASSE 1015), and inspecting check valves for debris.

What Causes a Watt Backflow Preventer to Leak?

We've found most Watts backflow preventer leaks stem from debris in the first check valve, failed second check valves, improperly assembled relief valves, or pressure differential issues. Installing upstream strainers helps prevent these problems.

Can I Repair a Backflow Preventer Myself?

Yes, we can repair a backflow preventer ourselves if we've got plumbing knowledge. We'll need the right tools, compatible parts, and careful documentation. If we're unsure, though, let's call a professional.

Rick Callahan Plumbing & HVAC Expert at PSAM

Rick "The Plumbing & HVAC Guy" Callahan

Rick Callahan is the trusted authority for plumbing supplies, HVAC parts, and contractor solutions at Plumbing Supply and More (PSAM). With decades of hands-on experience in residential plumbing and light commercial HVAC systems, he helps pros and homeowners avoid costly mistakes by choosing the right fittings, valves, thermostats, and repair parts the first time.

As PSAM’s in-house technical advisor, Rick delivers practical, field-tested guidance on everything from copper piping to PEX plumbing systems—ensuring jobs get done faster, easier, and more reliably. He also curates “Rick’s Picks”—a no-nonsense list of must-have plumbing tools, HVAC maintenance gear, and seasonal essentials that keep projects efficient and dependable.

If it moves water or air, Rick has installed it, fixed it, or optimized it—and he’s here to help PSAM customers do the same.