Armstrong-Yoshitake, Inc. GD-30 Instructies voor installatie en onderhoud - Pagina 2

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Improper adjustment of the pressure reducing valve may cause hunting, scale problems, water hammer, etc., and

damage to the valve itself. Damaged pressure gauges, leakage or opening of a bypass valve, or clogging of an inlet

strainer may cause problems similar to that of a malfunctioning reducing valve.

Adjust the valve as follows:

1. Close the gate valves before and after the pressure

reducing valve. Open the globe valve slowly in the

bypass line and blow down the inlet piping. Adjust the

opening of the bypass valve so the safety valve does

not blow. After blowing the system down, close the

bypass valve.

2. Slowly open the inlet side gate valve to the fully open

position, and partially open the outlet valve so only a

small amount of steam or air can pass.

Problem

The inlet pressure is too low or high.

The sensing port of the outlet pressure is clogged with

foreign matter.

The desired pressure

The valve size is smaller than what is required.

cannot be obtained.

The adjustment is not appropriate.

The inlet strainer is clogged by foreign substance.

The pressure gauge is not functioning properly.

The outlet pressure

The valve or valve seat is contaminated by foreign

substance.

rises higher than the

specified pressure

The by-pass valve is leaking.

The reducing ratio is excessively large.

Abnormal noise is

Water hammer (for steam service).

heard.

There is a fast closing valve near the PRV.

Start-Up and Adjustment Procedures

Troubleshooting Guide

Causes

3. To increase the downstream pressure, place your hand

on the top of the adjusting handle and pull vertically

up. When in the fully up position turn the handle

clockwise until the desired pressure is obtained on the

downstream pressure gauge.

4. Release the handle and it will automatically retract

which will lock the adjusting handle in place.

5. Slowly open the outlet valve to the fully open position.

Change the pressure to the appropriate level.

Disassemble and clean the sensing port.

Change the valve size to the appropriate one.

Readjust according to the adjustment procedure.

(See start-up procedure)

Disassemble and clean the strainer.

Replace the pressure gauge.

Disassemble and clean the valve or the seat.

Repair or replace the by-pass valve.

Reduce pressure by staging with second PRV.

Install a steam trap at the reducing valve inlet.

Provide as long a distance as possible between

the two valves.

Solutions