English – May 2002
This installation guide provides instructions for installation, startup,
and adjustment. To receive a copy of the instruction manual,
contact your local Fisher Sales
Office or Sales Representative or view a copy at
www.FISHERregulators.com. For further information refer to:
168 Series Instruction Manual, form 2256, D100275X012.
This product may be used as a safety accessory with pressure
equipment in the following Pressure Equipment Directive 97/23/EC
categories. It may also be used outside of the Pressure Equipment
Directive using sound engineering practice (SEP) per table below.
Maximum Allowable Pressures
6.9 bar (100 psi)
10.3 bar (150 psi)
168-1, 168-2,168H-1, and 168H-2:
10.3 bar (150
168-3, 168-4, 168H-3, and 168H-4:
2.8 bar (40 psi)
Diaphragm Pressure Ranges
168-1 and 168-3: 0.1 to 4.1 bar (2 to 60 psi)
168-2 and 168-4: 0.1 to 2.8 bar (2 to 40 psi)
168H-1 and 168H-3: 3.5 to 10.3 bar (50 to 150 psi)
168H-2 and 168H-4: 2.4 to 6.9 bar (35 to 100 psi)
Diaphragm Pressure Change Between
168-1, 168-2, and 168-3:
0.7 bar (10 psi)
0.5 bar (7 psi)
168H-1, 168H-2, and 168H-3:
1.4 bar (20 psi)
1.1 bar (16 psi)
4.0 bar (58 psi)
2.6 bar (38 psi)
: 6.9 bar (100 psi)
4.5 bar (65 psi)
Proof Test Pressure
All Pressure Retaining Components have been
proof tested per Directive 97/23/EC - Annex 1,
Operative Temperature Limits
-23.3 to 66°C (-10 to 150°F)
Only qualified personnel should install or service
a regulator. Regulators should be installed, oper-
ated, and maintained in accordance with interna-
tional and applicable codes and regulations, and
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 imme-
diately may create a hazardous condition.
Personal injury, equipment damage, or leakage
due to escaping fluid or bursting of pressure-con-
taining parts may result if this regulator is over-
pressured or is installed where service condi-
tions could exceed the limits given in the Specifi-
cations section, or where conditions exceed any
ratings of the adjacent piping or piping connec-
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 lim-
Additionally, physical damage to the regulator
could result in personal injury and property dam-
age due to escaping fluid. To avoid such injury
and damage, install the regulator in a safe loca-
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 male 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.
It is important that the regulator be installed so that the
vent hole in the spring case is unobstructed at all times.
For outdoor installations, the 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 regulator be-
neath eaves or downspouts, and be sure it is above the
probable snow level.
The recommended pressure limitations are stamped on the regu-
lator 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 pro-
vided 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.
The regulator is factory set at approximately the midpoint of the
spring range or the pressure requested, so an initial adjustment
may be required to give the desired results. With proper instal-
lation completed and relief valves properly adjusted, slowly open
the upstream and downstream shutoff valves.
1. The pressure/temperature limits in this installation guide and any applicable
standard or code limitation should not be exceeded.