The FEBCO Series 850 Inline Backflow Preventer is a bronze double check valve assembly built for non-health hazard applications such as irrigation, fire line, or industrial processing service. Two independently operating, spring-loaded check valves stop contaminated irrigation water from reversing into your potable supply, satisfying national plumbing codes and local water authority cross-connection requirements. Available here in 1/2" and 3/4" NPT sizes with standard ball valve shutoffs.
This series includes a freeze sensor (mounted to one of the four test cocks) that can alert facility personnel when temperature nears freezing, once activated with an add-on BMS/IMS connection kit. The all-bronze body with silicone elastomers and stainless steel springs carries a 175 PSI maximum working pressure rating and is approved by the Foundation for Cross-Connection Control and Hydraulic Research (USC). This assembly is not approved for drinking, dishwashing, or other human-consumption plumbing per FEBCO's product warning.
Specifications for the 1/2" and 3/4" sizes carried by DripWorks.
| Specification | Details |
|---|---|
| Assembly Type | Double Check Valve Assembly, Series 850 Small |
| Sizes Available | 1/2" NPT, 3/4" NPT |
| End Connections | NPT, ANSI/ASME B1.20.1 |
| Body Material | Bronze |
| Elastomers / Springs | Silicone / Stainless Steel |
| Max. Working Pressure | 175 PSI (12.1 bar) |
| Hydrostatic Test Pressure | 350 PSI (24.1 bar) |
| Temperature Range | 32°F to 140°F (0°C to 60°C) |
| Freeze Sensor | Included (requires add-on connection kit to activate alerts) |
| Approvals | ANSI/AWWA C510-92; USC Foundation for Cross-Connection Control and Hydraulic Research |
| Weight | 1/2": 4.2 lb | 3/4": 4.4 lb |
| Brand | FEBCO (Watts) |
| SKU | FEB85012 |
Step 1: Position the Assembly
Install the backflow preventer downstream of the water meter and upstream of any irrigation valves, timers, or fertilizer injectors, per your local water authority's requirements.
Step 2: Connect the NPT Ends
Thread the inlet and outlet NPT connections into your supply line, using thread sealant appropriate for potable/irrigation piping.
Step 3: Open Shutoff Valves
Slowly open the ball valve shutoffs on both sides of the assembly to avoid water hammer.
Step 4: Test Annually
Have the assembly tested by a certified backflow tester at installation and at least once per year, or as required by local code.
Can this backflow preventer be used for drinking water lines?
No. FEBCO's own product literature states it is illegal to use this assembly in any plumbing system providing water for human consumption, such as drinking or dishwashing.
It is designed strictly for non-health hazard applications like irrigation, fire lines, or industrial processing. Always consult your local water authority before installation.
Does the freeze sensor automatically alert me to freezing conditions?
No, not on its own. The freeze sensor is a passive component and requires a separate add-on connection kit to communicate with a building or irrigation management system.
Without the connection kit installed, the sensor cannot send alerts, so it should not be relied on as a standalone freeze-protection method.
What sizes does DripWorks carry?
DripWorks stocks the FEBCO 850 in 1/2" and 3/4" NPT sizes, both with standard ball valve shutoffs.
Larger sizes exist in FEBCO's full lineup but are not currently carried on this listing.
How often should this assembly be tested?
Most water authorities require annual testing by a certified backflow tester, in addition to testing at initial installation.
Check with your local municipality, as testing frequency and certification requirements vary by jurisdiction.
Please note before purchasing:
Pair your backflow preventer with these components for a complete, code-compliant irrigation setup:
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