Since last December I observed my sprinkler valve was leaking water. I went ahead and shut off the isolation valve and kept it off until this weekend to fix it, as we have finally reached the dry season and further procrastination may result in serious plant damages. See the problem video here: (in spoken Chinese)

Thanks to this video below, I was able to clean out the gummy sediment from years of operation: I was glad that valve was still in good shape such that I didn’t have to replace the whole value.

There are different kinds of sprinkler valve, our Lawn Genie closely matches the screw-cap type like the one in this video:

The valve operation among the various vendors are similar. It consists of a diaphragm and a solenoid (the black cylinder that connects to the electrical wire). Without the electricity, the valve is normally shut off. When the electricity is applied, the solenoid pull up the plunger, releasing the water above the diaphragm, allowing the water to go through. Here is a good explanation of how it works.

Lessons learned:
1. Check Youtube/Google the available resources before commencing the repair work. Even if you have done the same repair before, there are always something that can refresh your memory and new tricks others have learned.
2. Keep clear of the work area so that you can place all the parts clearly visible in front of you. I almost lost the tiny plunger rod and had to look for a long time – not cool.