Nelson 800 Series User Manual

4 pages

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Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: 509.525.7660 Fax: 509.525.7907 E-mail: info@nelsonirrigation.com Web site: www.nelsonirrigation.com

VALVE CONTROL FUNCTION:

The PRESSURE REDUCING MANUAL ON-OFF model of the 800 Series Control

Valve is a hydraulically operated sleeve type valve with a pressure

reducing pressure control kit and a manual on-off. The flow through

the valve is controlled by a rubber sleeve which is actuated by

hydraulic pressure. When the selector is pointed to the "AUTO" position

then the valve will automatically reduce a higher inlet pressure to a

constant lower downstream pressure. The pressure reducing control

is adjustable to give a constant down stream pressure even with

fluctuating upstream pressure. The manual selector is used to

manually open or close the valve. Pointing the manual selector

handle to "OPEN" or "CLOSE" will override the "AUTO" control. Pointing the

Manual Selector handle mid way between "OPEN" and "CLOSE" will

hold the valve partly open.

The information on this sheet is for the

PRESSURE REDUCING MANUAL ON-

OFF control function with plastic tubing and internal or external filter

option (items D2 - D4, D12-D13, E1, H2 - H3 control function on

the VALVE SELECTION GUIDE apply to this sheet).

800PR5

800 SERIES CONTROL VALVE — CONTROL FUNCTION and MAINTENANCE

PRESSURE REDUCING MANUAL ON-OFF

MANUAL

SELECTOR

INTERNAL

FILTER

PRESSURE

REDUCING

CONTROL

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Other manuals for Nelson 800 Series

Application Guide19 pages

Manual4 pages

Questions and Answers:

K
Kim GomezAug 3, 2025
What to do if Nelson Control Unit valve will not open or has excessive pressure drop?
- A
  ashley02Aug 3, 2025
  If the Nelson Control Unit valve doesn't open or shows a significant pressure drop when the manual selector valve is in the “OPEN” position, first, inspect all tube lines and fittings for any blockages or kinks. Also, ensure that the upstream pressure is sufficient. If the issue persists, the flow may be blocked by debris; in this case, remove the valve from the line and clean it thoroughly.
N
Nicole Watkins PhDAug 17, 2025
What to do if Nelson Control Unit valve will not close?
- M
  Michael PerezAug 17, 2025
  If the Nelson Control Unit valve does not close when the manual selector valve is in the “CLOSE” position, begin by checking all tube lines and fittings for leaks. When removing control tube lines, apply opposing force as shown in the manual. Ensure water flows through the tube "U" connecting the upstream side of the main valve to the “CLOSE” port of the manual selector valve. A blocked filter or damaged sleeve may also be the cause; clean the filter or replace the sleeve accordingly.

Nelson 800 Series Specifications

General

Brand	Nelson
Model	800 Series
Category	Control Unit
Language	English

Summary

Valve Control Function

Manual On-Off Operation

Details how the manual selector controls the valve's open or close state, overriding auto mode.

Pressure Reducing Control

Explains how the valve automatically reduces higher inlet pressure to a constant lower downstream pressure.

Troubleshooting Guide - Valve Not Closing or Opening

Valve Fails to Close

Checks for leaks, tube 'U' flow, and filter blockage when the valve is in the 'CLOSE' position.

Valve Fails to Open or High Pressure Drop

Checks for blockages, adequate upstream pressure, and water volume for opening.

Troubleshooting Guide - Pressure Regulation Issues

Valve Will Not Pressure Regulate

Checks for correct line connections, open isolation valves, and stuck spool valve in pressure control.

Unstable Regulated Pressure

Addresses unstable pressure and water discharge by checking for trapped air in the system.

Schematic with External Filter

External Filter Kit Configuration

Diagram illustrating the valve setup with an external filter, manual selector, and connections.