Every year plumbing technicians receive inquiries on a simple approach for winterizing backflow irrigation systems before the first freeze hits – known as a quick drain.
Depending on the specifics of your system, this process varies. However, generally speaking, you would shut off water to your sprinklers at the main valve (usually near the backflow preventer) and open all isolation valves and test cocks before switching them back on.
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1. Turn Off the Water
Backflow preventers prevent water from your sprinkler system from flowing back into the drinking water supply in your home, protecting both its own life and that of others. They come equipped with two valve shut-off handles and can be conveniently found behind irrigation boxes.
Unscrew these valves using a flathead screwdriver, and water will start draining out – make sure a bucket is nearby to catch this excess!
2. Disconnect Compressor
Backflow preventers are required for irrigation systems, fire sprinkler systems in large buildings, and other commercial properties in order to prevent back siphonage or back pressure that could potentially pollute municipal water supplies.
Without backflow prevention devices, clean drinking water could come into contact with used water that contains bacteria, chemicals, or other contaminants that are potentially hazardous for consumption and bathing use. Winterizing a backflow preventer involves blowing out its isolation valves using a compressor with sufficient CFM ratings and psi pressure ratings for best performance.
3. Open Isolation Valve
Backflow preventers are devices designed to isolate irrigation water from potable (water suitable for drinking) water supply in order to stop contaminants from sneaking their way into your sprinkler system.
Isolation valves can usually be found in green valve boxes near backflow preventers or water meters. To open an isolation valve, simply turn it to its open position by turning off its cover.
Locate and open up the test cocks using a flat-blade screwdriver; water may initially come pouring out with some force but should subside quickly.
4. Close Isolation Valve
Your backflow preventer ensures water flows in one direction, protecting against irrigation water contaminating both your family’s drinking supply and city infrastructure. Typically made out of brass pipes protruding from the ground surface.
Your choice of backflow preventer depends on the severity of the risk present in each situation, from indoor sinks and tubs to industrial sites with hazardous operations. An air gap may suffice in low-hazard settings; otherwise, you will require a double-check valve assembly.
5. Open Test Cocks
Reduced Pressure Zone Assemblies (RPZAs) are the go-to backflow device in fire protection systems.
Comprising two spring-loaded approved check valves connected by a differential relief valve and with tightly closing shut-off valves before and after, as well as four test cocks for inspection and testing purposes, an RPZA should provide protection from contamination of irrigation systems and home plumbing piping.
Open and close test cocks regularly to make sure no trapped water lingers in its backflow device or irrigation system – this step should help ensure this prevents possible future contamination of irrigation systems as well as house piping.
6. Close the Test Cocks
If your residential dual check backflow assembly contains test cocks, be sure to open them and drain away any water accumulating inside it or its pipes.
A Reduced Pressure Zone Assembly (RPZD) is one of the most frequently installed backflow preventers, featuring two spring-loaded check valves with differential relief valves in between, two tight-closing shut-off valves on each side, as well as four test cocks for inspection and testing by an accredited backflow inspector.
7. Close Compressor Valve
Drain your backflow preventer regularly to eliminate water contamination, especially if it has started leaking due to thermal expansion or dirt accumulation in its seal.
Backflow occurs when there’s an abrupt change in pressure, such as when pipes freeze or someone taps a fire hydrant, that results in siphoning of contaminated water back into your city water supply line.
You may have noticed strange colors or smells in your tap water supply line; to stop backflow, temporarily close test cocks by rotating them a quarter turn (handles must line up with flow); this will drain the PVB.
8. Open Sprinkler Station
Backflow preventers prevent pressurized, potentially contaminated water from being drawn back into potable supplies, protecting PVC and polyethylene pipes in freezing climates from water that might freeze up and crack them, or cause internal damage to backflow devices.
Turn off the water supply to your sprinkler station at its main valve, which should be near your water meter. Next, open up both drain valves on your backflow preventer device – they have two blue levers or screws perpendicular to their faceplate – in order to stop backflow from occurring.
