Landscape Architect Articles

LCN June 2006 Inside Irrigation05-31-06 | News

Troubleshooting Multi-zone Valves

Cam-driven index valves activate one zone after another. Replacement cams are used to change a valve?EUR??,,????'?????< Photo courtesy of Baseballusa.com

The tips below are based on information tailored for K-Rain 4000 and 6000 series valves. Much of the information will apply to other brands and other designs.

Q: What do I do if my valve doesn’t change or cycle to the next zone or outlet?

A: This happens when the stem and disk assembly is not rotating when the water flow is turned OFF and then back ON.

Suggested solutions:

1. Make sure there is no debris inside the cam. Clean and carefully reinstall the cam.

2. If fewer than the maximum number of outlets are being used, check the installation of the cam. Ensure that the stem and disk assembly is not being held down by an improperly installed cam.

3. Remove the valve top and check for proper movement of the stem and disk assembly. Check for and remove any debris or foreign objects that may jam or retard the movement of the disk.

4. Check for freedom of movement of stem and disk assembly up and down over the center pin in bottom of valve. Scale deposits may build up on the pin and hold stem and disk assembly down. Clean pin and again check for freedom of movement.

5. Be sure that all operating outlets are not capped and that the flow to operating zones is not restricted in any manner. This would cause pressure to build up in the valve and lock the stem and disk assembly in the down position.

6. The backflow of water from uphill lines may be preventing the valve from cycling properly. This can happen when the valve is placed too far below an elevated irrigation line. If the valve cannot be placed close to the high point of the system, a check valve should be installed near the valve in the outlet line that runs uphill from the valve.

Q: Water is coming out of all the valve outlets. What do I do?
A1: This problem can be caused when the stem and the disk assembly is not seating properly on the valve outlet. If so try this:

1. Check for sufficient water flow. A minimum of 10 GPM is required to properly seat the disk. For water flow between 6 and 10 GPM, a stem and disk assembly with a lighter spring is available.

2. Remove the valve top and check the inside walls to ensure that nothing is interfering with the up and down movement of the stem and disk assembly inside the valve.

3. Make sure that the operating outlets are not capped and that the flow to the operating zones is not restricted in any manner.

A2: Too many sprinkler heads on a zone will cause insufficient pressure for the disk to seat firmly over the valve outlet. If so reduce the number of heads on the zone to obtain the proper sprinkler operating pressure.

Q: How can I keep the valve from skipping outlets or zones?

A1: For a pump installation, the pump may be losing its prime, causing the water flow to surge. This will cause the valve to cycle quickly several times, skipping one or more zones. Verify that the flow to the valve is constant by removing the valve top and watch the flow when the pump is turned ON after having been turned OFF for at least 15 minutes. The flow should be steady and uninterrupted. In addition:

1. Seal any pump suction line leaks.

2. Replace or install suction line. Check valve to prevent pump from losing its prime.

A2: The stem and disk assembly is being advanced past the desired outlet. To correct: Ensure that the correct cam for the desired number of zones is installed and that the outlet lines are installed to the correct outlet parts of the valve as indicated by the zone numbers on the top of the cam.
More information: k-rain.com: ?EUR??,,????'?????<

This 4000-series multi-zone valve is used for larger applications and works like a pistol revolver to deliver water to each zone?EUR??,,????'?????< Photo courtesy of K-Rain

Irrigation Insights

15-50: Gallons per minute. The capacity of K-Rain?EUR??,,????'?????<
15: Minutes. Time pump should be turned off before testing valve for steady and uninterrupted flow. Source: www.k-rain.com