If the indexing valve is sticking, whether it be on random zones or on all zones, it’s usually easy to fix. Most times it’s one of a handful of issues and generally simple to diagnose.
The first thing to do is to make certain the system is inactive. Once the system is inactive, remove the four screws on the top of the unit. The four screws fasten two items to the valve top, those are the cam and the cam cover.
The following processes are meant to be a sequence of troubleshooting steps.
#1 – Testing for a Vacuum
After removing the four screws, remove the cam cover. Pay close attention as you remove it and listen for a ‘suction’ sound which would indicate a vacuum. This would move a vacuum to the top of the list of most likely culprits.
The 1/2″ Vacuum Relief Valve is designed to provide instant air and vacuum relief. This works great paired with the Snap on Saddle (sold separately)
#2 – The Basic Mechanical Test
With the the cam cover removed, hold the cam down as if the screws are still securing it to the valve top and press down on the stem. Now release the stem. You should notice it catching the curved teeth on the cam on the way down and rotating, and once you release it you should notice the stem popping back up and rotating a bit more.
Press and release the stem (with the cam being held in place!) 10-12 times, you should be able to tell if it’s working properly by this point.
Pay special attention to the tab that hangs off of the top of the stem. This tab comes into contact with the cam on the downstroke and if damaged will cause the valve to stop indexing.
At this point, if we still have no real clues or direction we have to look deeper.
Remove the six or eight screws around the perimeter and unthread the coupling nut on the valve union. Remove the entire upper half of the indexing valve.
#3 – Clean It Up And Check for Obstructions
Is the inside of the housing clean? Is there glue in the housing? Check the disk, is there a large buildup of iron or anything else on it? Any critters (snails, lizards, frogs, etc) under that disk?
A scrubby sponge and a little dish soap will handle this fairly easily, no need for anything else.
#4 – Got Sand?
If you know you have a sand issue remove the four screws from the valve top and remove the cam cover. Underneath the cam cover, you will see two items, one is the cam (numbers molded into it) and the other is the stem which sticks up through the middle of the cam.
In the top/middle of the stem is a hole for the cam cover and zone indicator to fit into. If it’s full of sand the stem can’t move back to up position and the valve will cease to rotate.
Still have an issue?
Call us during our normal hours of operation and let’s discuss the issue. The phone number is (561) 624-3308.