Frozen Sprinkler Valve

Effects of Frozen Valves

• In most sprinkler systems, water flows from the main supply line into an assembly of pipes and valves known as the manifold. When water freezes inside these pipes, it expands. Water that freezes in a manifold will creep into the valves and continue to expand, creating pressure on the walls and internal components of a valve. Most of the time, frozen water will crack the body of a valve or damage the plastic diaphragm inside the valve that releases water to the sprinkler heads.

Diagnosing Frozen Valves

• Loosening the solenoid on top of the valve will normally allow water to flow from the valve to the rest of the system. If you loosen the solenoid and water does not flow, the valve is currently frozen. Turn the water off by turning the ball valves on the brass pressure vacuum breaker above the manifold. Loosen the screws on the sides of the faulty valve with a screwdriver and pull the two pieces of the valve apart for inspection. Check for signs of frozen water, cracks to the inside of the plastic housing and damaged diaphragms.

Repairing Frozen Valves

• If there are cracks on the valve, it must be replaced with a new one. Remove the old valve by loosening the locking nuts on either end of the valve and setting a new valve in place before tightening the nuts. If only the internal components of the valve are damaged, they can be replaced using a valve repair kit that's available at most hardware stores. The repair kit includes an O-ring, diaphragm and spring. You can replace only the parts that are broken or all of them at once.

Preventing Frozen Valves

• The best way to fix a frozen sprinkler valve is to prevent it from freezing in the first place. To accomplish this, you must drain all of the water out of the valve before the first hard freeze of the season. Most sprinkler manifolds contain a drain cap at the end of the assembly. Remove this cap to drain all of the water out of the manifold, including all of the valves. This will prevent water from expanding inside the manifold and from damaging the valves.