The FEBCO 765 Pressure Vacuum Breaker (PVB) protects your home's potable water supply from back-siphonage of irrigation water, fertilizers, and other contaminants. Installed downstream of your water source and at least 12 inches above the highest sprinkler head or outlet, this all-bronze assembly combines a spring-loaded check valve and air-opening port in one compact unit. Available in 3/4" and 1" sizes, it's rated for a maximum working pressure of 150 psi (10.3 bar). Pair it with a compatible irrigation valve to complete your backflow-protected system.
This model includes a built-in freeze sensor that detects when temperatures near freezing; note that the sensor is passive out of the box, so an add-on BMS/IMS connection kit (available separately from FEBCO) is required to activate freeze alerts. All internal parts are serviceable in line from the top of the unit. Because this is a PVB assembly rather than an RPZ, it must never be installed where backpressure conditions could occur downstream.
Detailed specifications for system planning.
| Specification | Details |
|---|---|
| SKU | FEB765BV34 |
| UPC | 0643925001112 |
| Available Sizes | 3/4" and 1" |
| Body Material | Bronze (elastomers: nitrile) |
| Maximum Working Pressure | 150 psi (10.3 bar) |
| Hydrostatic Test Pressure | 300 psi (20.7 bar) |
| Temperature Range | 32°F to 140°F (0°C to 60°C) |
| Freeze Sensor | Included (passive; requires optional add-on connection kit to activate BMS/IMS alerts) |
| Installation Clearance | Minimum 12" above the highest downstream outlet/piping |
| Approvals | USC Foundation for Cross-Connection Control and Hydraulic Research |
| Brand | FEBCO (a Watts brand) |
Key steps for a proper, code-compliant installation.
Step 1: Flush the Line
Before installing the valve, flush the supply line of all foreign material to prevent debris from fouling the check valve.
Step 2: Position Correctly
Install the valve only in the vertical, upright orientation shown in the manufacturer's instructions. Installing it in any other position will cause the device to malfunction.
Step 3: Maintain Clearance
The assembly must be installed at least 12 inches above the highest downstream outlet and the highest point in the downstream piping, in a location accessible for periodic testing and maintenance.
Step 4: Pressurize and Test
After installation, fill the assembly with water, open the inlet valve to pressurize the unit, then slowly open the outlet valve to fill the downstream line. Test the device to confirm proper operation before regular use.
What's the difference between the 3/4" and 1" versions?
Both use the same FEBCO 765 design; the difference is simply the pipe connection size, so choose whichever matches your irrigation mainline.
If you're unsure which size your system needs, measure the outside diameter of your existing supply line or check your irrigation plans before ordering.
Does the freeze sensor automatically alert me to freezing temperatures?
Not by itself. The sensor is a passive component until an add-on BMS/IMS connection kit is installed to relay the alert to a building or irrigation management system.
Without the connection kit, the sensor cannot communicate with any other device, and freezing conditions can still damage the assembly if it isn't properly winterized.
Can I install this where backpressure might occur?
No. The 765 is a pressure vacuum breaker (PVB), designed only to protect against back-siphonage, not backpressure.
If your system could experience backpressure conditions, consult local codes — a reduced pressure zone (RPZ) assembly may be required instead.
How do I prepare this backflow preventer for winter?
Drain the assembly through properly installed drain valves (not the test cocks alone), and leave shutoff valves in a half-open position for the season.
Refer to the winterization instructions in the Downloads section below for the complete draining procedure specific to this model.
Please note the requirements for this component:
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