Trickle systems using ponds, lakes, streams and springs as a source of water are prone to high levels of algae and bacteria. The visible signs are seen as slimy film, usually dark in color on the inside of the pipes and tubing. Chlorine will kill such growth and keep it in check. Before the trickle system is shut down for the winter, chlorinated water should be run through each zone. The suggested concentration for this winterizing procedure is 20-30 ppm. The key is to get this concentration to all parts of the system, let it sit in the system wherever possible for several hours, then drain down the system. At start up the following season all trickle lines should be flushed of any foreign material.
PVC pipe becomes brittle at low temperatures and has no elastic properties, therefore it is very important to completely drain all the water from sections in areas subject to freezing.
Gate and ball valves will not tolerate freezing. A gate valve, when closed traps water in the bonnet. A ball valve seals water inside the ball. If the valve is closed when water is in the line and the line drained without opening this valve, the water trapped above the gate or inside the ball will freeze and have no place to expand. The trademark of freezing is very distinctive: a ball valve will pop the side out, and a gate valve will split its bonnet, packing nut or have a hairline crack down its side.
Solenoid valves are best winterized by leaving them manually open for the winter. The manual bleed system on valves varies by model and manufacturer, but is usually a thumb screw, or lever on the bonnet.
Automatic control valves, such as pressure reducing, pressure relief, or combination valves contain external control tubing, pilots and other parts requiring special care to thoroughly drain. If the entire valve can be easily removed from the piping, it may be simplest to store the valve in a heated location for the winter. If removing the valve is not practical, crack open control tubing connections wherever necessary to thoroughly drain all external parts. The valve bonnet should also be loosened or removed to remove all water from the top of the diaphragm.
Always drain a pump by the lowest plug or drain cock on the volute, breaking a connection or opening a plug at the top to let air in. If the pump discharge plumbing is left connected, (as is often the case with electric pumps), and only the bottom drain is opened, a vacuum can be created when the water drains, leaving much of the volute full of water. (Hint: If your pump has a drain plug still in it, take it out, throw it away, and replace it with a drain cock or drain valve. Drain plugs usually become rounded and extremely difficult to remove, not to mention difficult to get to, making an unpleasant project out of a simple task.)
Along with the pump, don't forget the suction line. Pull it out of the water, drain it and secure the open pipes to prevent furry creatures from making a winter home in the pipe or pump. In the spring I always get a couple of calls from frustrated individuals trying to understand why their pump won't pump water, or won't pump the pressure and/or volume it used to. Rocks, pebbles, nut shells, leaves, and animals from mice to snakes have found their way into the eye of the impeller and go no farther. Needless to say, simply plugging open ends will save alot of time and headache.
Ever notice how pressure gauges never seem to last long? Most pressure gauges I have replaced were damaged by freezing. Water becomes trapped inside the gauge, which freezes and ruins it. There usually is no external sign of damage other than the needle being pinned to the end or showing pressure even when there is none. The best solution to protecting gauges is removing them for the winter and storing in a warm place.
Since controllers are subject to power and lightning surges all year, I recommend disconnecting them for the off-season whenever possible. Both the input and output wires should be removed or unplugged. If wires must be removed from terminals, use wire markers to identify them to make reconnection simple.