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Introduction

This installation guide provides instructions for installation, startup 

and adjustment. To receive a copy of the instruction manual, contact 

your local Sales Office or view a copy at www.fisher.com. For further 

information, refer to: 912N Series Instruction Manual, D100317X012.

PED Category

This product may be used as a pressure accessory with pressure 

equipment in the following Pressure Equipment Directive categories. 

It may also be used outside of the Pressure Equipment Directive 

using sound engineering practice (SEP) per table below. For 

information on the current PED revision, see Bulletin: 

D103053X012

.

PRODUCT SIZE

CATEGORIES

FLUID TYPE

1/4 and 3/8 NPT

SEP

1

Specifications

Body Sizes and End Connection Styles

Inlet:

 1/4 NPT

Outlet:

 1/4 or 3/8 NPT

Maximum Allowable Inlet Pressure

(1)

17.2 bar / 250 psig

Outlet Pressure Ranges

(1)

See Table 1

Maximum Allowable Outlet Pressure

(1)

Emergency Outlet Pressure:

 1.4 bar / 20 psig

Recommended Outlet Pressure to Avoid Internal Part 

Damage:

 0.21 bar d / 3 psid above outlet pressure setting; 

provide external relief if start-to-discharge point exceeds 

0.21 bar d / 3 psid

Proof Test Pressure

All Pressure Retaining Components have been proof tested 

per Directive.

Temperature Capabilities

(1)

-29 to 71°C / -20 to 160°F

Installation

!

WARNING

Only qualified personnel should install or service 

regulator. Regulators should be installed, 

operated and maintained in accordance with 

international and applicable codes and regulations 

and Emerson Process Management Regulator 

Technologies, Inc. instructions.
If the regulator vents fluid or a leak develops in 

the system, it indicates that service is required. 

Failure to take the regulator out of service 

immediately may create a hazardous condition. 
Personal injury, equipment damage, or leakage 

due to escaping fluid or bursting of pressure-

containing parts may result if this regulator 

is overpressured or is installed where service 

conditions could exceed the limits given in the 

Specifications section, or where conditions 

exceed any ratings of the adjacent piping or 

piping connections.

To avoid such injury or damage, provide pressure-

relieving or pressure-limiting devices (as required 

by the appropriate code, regulation or standard) to 

prevent service conditions from exceeding limits.
Additionally, physical damage to the regulator 

could result in personal injury and property 

damage due to escaping fluid. To avoid such injury 

and damage, install the backpressure regulator in 

a safe location.

Clean out all pipelines before installation of the regulator and check 

to be sure the regulator has not been damaged or has collected 

foreign material during shipping. For NPT bodies, apply pipe 

compound to the external pipe threads. For flanged bodies, use 

suitable line gaskets and approved piping and bolting practices. 

Install the regulator in any position desired, unless otherwise 

specified, but be sure flow through the body is in the direction 

indicated by the arrow on the body.

Note

It is important that the backpressure regulator 

be installed so that the vent hole in the spring 

case is unobstructed at all times. For outdoor 

installations, the backpressure regulator should be 

located away from vehicular traffic and positioned 

so that water, ice, and other foreign materials 

cannot enter the spring case through the vent. 

Avoid placing the backpressure regulator beneath 

eaves or downspouts, and be sure it is above the 

probable snow level.

Overpressure Protection

The recommended pressure limitations are stamped on the 

regulator nameplate. Some type of overpressure protection 

is needed if the actual inlet pressure exceeds the maximum 

operating outlet pressure rating. Overpressure protection should 

also be provided if the regulator inlet pressure is greater than the 

safe working pressure of the downstream equipment. 
Regulator operation below the maximum pressure limitations 

does not preclude the possibility of damage from external 

sources or debris in the line. The regulator should be inspected 

for damage after any overpressure condition.

1.  The pressure/temperature limits in this installation guide and any applicable standard 

or code limitation should not be exceeded.

Table 1

. Outlet Pressure Ranges

AVAILABLE 

CONFIGURATION

OUTLET PRESSURE RANGE

APPROXIMATE POINT ABOVE 

OUTLET PRESSURE SETTING 

AT WHICH INTERNAL RELIEF 

STARTS TO DISCHARGE

mbar

In. w.c.

mbar

In. w.c.

912N Series

7 to 17 

12 to 25

23 to 32

30 to 60

3 to 7

5 to 10

9.25 to 13

12 to 24 

12 to 52

20 to 75

40 to 97

40 to 210

5 to 21

8 to 30

16 to 39

17 to 3 psig

0.03 to 0.18 bar

0.18 to 0.34 bar

0.5 to 2.7 psig

2.7 to 5 psig

0.05 to 0.47 bar

(1)

0.26 to 0.86 bar

(1) 

0.7 to 6.8 psig

(1)

3.8 to 12.5 psig

(1)

912N Series 

with handwheel

20 to 60

0.18 to 0.34 bar

8 to 24

2.7 to 5 psig

75 to 88 

0.37 to 0.46 bar

(1)

30.3 to 35.4

5.4 to 6.7 psig

(1)

1.  Internal Relief Performance is only adequate for relieving minor build-up situations. 

External relief is required if start-to-discharge point exceeds 0.21 bar d / 3 psid.

912N Series

Installation Guide 

D100317X014
English – June 2010

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