Don't Make This Mistake
Drip irrigation professionals note that the most common mistake made by first time drip irrigation DIYers is over-tightening. More specifically, over tightening of hose thread head assembly parts. Just a quick review, a head assembly consists of a timer(optional), backflow preventer, filter, pressure regulator, and tubing adapter. It is human nature to crank down on something and wanting it to be as tight as possible when installing threaded parts (especially ones that will hold water). However, over tightening head assembly parts for a drip irrigation system can actually cause the parts to crack or develop hairline fractures that will allow water to seep out. We recommend simply hand tightening the parts to each other.
In addition, we recommend ensuring each part has a washer installed before installing, that is if you are using hose thread fittings. Pipe thread fittings do not use washers and are not compatible with hose thread fittings.
What if There is a Leak?
Of course, if you turn on your system and see that water is leaking out of a connection point, then go ahead and give that spot a little more torque to seal up the leak. Even in this situation be gentle. Again, before cranking down on any leaking area, you will want to make sure that the washer has not fallen out and that it is still in good working order. Missing washers are by far the largest reason for leaking parts.
While we are talking about head assembly parts and leaks, it is a good time to talk about backflow preventers. We also get a lot of emails saying that their backflow preventer leaks but only when the system turns off. This is actually good news. The backflow preventer is designed to release water when the system shuts down. The reason for a backflow preventer is to keep water in the drip irrigation system from getting back into the main water supply. Once the system is turned off and the pressure begins to drop, the backflow preventer, otherwise known as ‘check valve’, opens up and releases any water trying to flow backward due to the back pressure in the line. So the backflow preventer will release water after the system is turned off. If you see this, rest assured that your system is working as it should be.
One last note on head assemblies and leaking. The head assembly components for drip irrigation are not designed to be under constant pressure. The maximum amount of time these parts are designed to be pressurized is 12 hours. Never install them above a timer. If they are left under constant pressure they will fail.
Pliers? Wrenches? No!
Never, in any circumstance use tools like pliers and wrenches to “tighten” the hose thread head assembly connections. We get a dozen or so emails every year from customers stating that they can’t figure out why some piece in thier head assembly started leaking because they made sure the connections were tight using a wrench. It is always hard to break the bad news that they damaged the item by using a wrench and that is the cause of the leak. Please refrain from using tools to “tighten” your head assembly components.
Here is a sample image of a standard head assembly (including a timer) for 1/2" poly tubing:
