Grain-systems PNEG-526 User Manual download pdf (Page 169)

To avoid excessive turbulence, the connection should be

clean and smooth on the inside and be located in straight

pipe clear of valves and fittings. Keep the inside of the

control line clean and protect it from corrosion. Pitch it

away from the regulator and avoid moisture pockets. It

must be strong (

" for 121-8 and 121-12,

" for 121-

16, or larger steel tubing or pipe is preferred). It must be

well protected against breakage (remember...regulators

open wide if the control line breaks).

9. Make sure the regulator is correctly connected and

adequately supported and pipe joints are tight.

Introduction

The Model 121 Regulator represents a combination of capacity,

performance and value...

Streamlined body passages provide large capacity. An external

control line is required from lower case to control piping. The 121

has a fast speed of response, yet is stable in operation. Soft seats

assure positive tight shutoff. Orifices are replaceable. Springs

are color coded.

And it is also available as a zero governor or atmospheric regula-

tor, a differential regulator, a relief valve or backpressure regula-

tor, vacuum regulator or vacuum breaker.

Installation

1. Examine the regulator for shipping damage.

2. Check nameplate data. Be sure regulator conforms with

what was ordered.

3. Inside of regulator and piping must be clean and free of

dirt. Remove all dirt and debris before installing regulator.

Failure to remove dirt/debris could result in regulator dam-

age or trouble.

4. Remove all shipping screens and covers from the regula-

tor. Do not let dirt get inside the regulator.

5. Install the regulator.

Make sure the inlet and outlet are correctly connected.

High pressure connects to the inlet. The flow arrow must

point downstream.

6. Screwed connections must conform with good piping prac-

tice free of excess thread engagement per ANSI B2.1

Apply pipe joint compound to male threads only.

7. The Model 121 Regulator is usually right side-up as shown

on the Typical Installation drawing (See Page 2). It may,

however, be installed upside down. Although, when inverted

it may be necessary to readjust the set-point.

Caution: Do not install sideways. The diaphragm should

be horizontal.

8. On indoor installations requiring venting outdoors, run the

vent piping as short and direct as possible with minimum

bends and elbows. Use the same size or larger pipe as

the vent connections on the regulator. With natural gas, or

any other hazardous gas, vent to a safe place outdoors in

case gas should accidentally be discharged. Screen and

protect the opening outdoors to guard against water, ice,

dirt, debris or insects.

Install the control line. Connect it into the outlet piping at

least 5 pipe diameters downstream from the regulator.

Regulator Installation and

Maintenance Instructions

Model 121

Regulators

Start-Up

A. The inlet and outlet shutoff valves should both be closed. If a

by-pass is used, the by-pass valve should also be closed.

B. Note the set-point (set-point is the outlet pressure the regula-

tor is adjusted to deliver). Regulator is factory adjusted to the

set-point specified on the order.

CAUTION: This caution applies where the piping downstream

of the outlet shutoff valve is pressured. That pres-

sure must not exceed the regulator set-point by

more than the pressure noted (see “Maximum

Emergency Pressures”, Page 18).

C. Slowly and carefully open the inlet shutoff valve just enough

to allow inlet pressure to build up slowly in the regulator until

it is fully pressured.

CAUTION: During start-up, a pressure gauge must be used

on the regulator outlet pressure and carefully

watched. While inlet pressure builds up, outlet

pressure must not exceed set-point by more than

1 psi. If outlet pressure begins to exceed set-point

by more than 1 psi, close the inlet shutoff valve.

This indicates the regulator is not closing properly.

Check and make necessary corrections before pro-

ceeding with start-up.

If regulator outlet pressure exceeds set-point by

more than the pressure noted, refer to “Maximum

Emergency Pressures”, Page 18 for instructions.

D. Check installation for leaks.

E. Slowly open the outlet shutoff valve to allow a small flow (ap-

proximately 1000 SCFH). Make sure the flow of gas does

not create a hazard.

NOTE: If piping downstream of outlet shutoff valve is pres-

sured, see “CAUTION” under B.

F. With gas flowing, check for correct inlet and outlet pressures.

It may be necessary to further open the inlet shutoff valve to

maintain full inlet pressure.

G. Make sure the regulator closes tight (tight lock-up). To do this,

reduce flow to zero by slowly closing the outlet shutoff valve.

Outlet pressure should not exceed set-point by more than

6" w.c.

H. Fully open inlet and outlet shutoff valves. Do this slowly and

carefully. Watch pressure gauges.

I. Complete start-up by making sure there are no leaks.

CAUTIONS:

a. On backpressure regulators and relief valves the

external control line connects into the inlet piping,

5 pipe diameters upstream from the regulator.

b. Do not install any automatic shutoff device that

closes completely between the regulator and the

control line connection into the piping.

NOTE

• Do not exceed the regulator’s pressure ratings. The

regulator outlet has a lower pressure rating than the

inlet. Do not expose the regulator outlet or control line

to inlet pressure.

Regulator with external control may be used as an

upstream monitor or upstream regulator in a monitor

set. The control line must connect into the outlet pip-

ing downstream of the downstream regulator.

• If the regulator is to be moved to another location,

make sure its construction is compatible with the pres-

sure and flow conditions.

Temperature Limits

The Model 121 Regulator can be used for flowing temperatures

from –20°F to 150°F.

Buried Service

The Model 121 Regulator is not recommended for buried service.

RM-1328 Rev. 9

1 2 ... 164 165 166 167 168 169 170 171 172 173 174 ... 191 192

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Grain-systems PNEG-526 User Manual Page 169

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