Failure to follow these instructions or
to properly install and maintain this
equipment could result in an explosion
and/or re causing property damage and
personal injury or death.
Fisher® relief valves must be installed,
operated and maintained in accordance
with federal, state and local codes,
rules and regulations and
manufacturer’s instructions.
If a leak develops or if the outlet
continually vents gas, service to the
unit may be required. Failure to correct
trouble could result in a hazardous
condition. Only a quali ed person must
install or service the unit.
Call a gas service person to service the
unit. Only a quali ed person must install
or service the regulator.
289 Series
18702
2 NPT TYPE 289H
Introduction
Scope of the Manual
This manual provides instructions for installation,
maintenance and parts ordering information for
the 289 Series relief valves. Instructions for other
equipment used with these relief valves can be
found in separate instruction manuals.
Description
The 289 Series pressure relief valves (see Figure 1)
are throttling relief valves used downstream of
pressure regulators to protect the downstream system
from overpressure. These relief valves can be used for
natural gas, air, propane or other noncorrosive, gas-
ow service.
W18701
1 NPT TYPE 289H
Figure 1. Type 289H Relief Valves
D100280X012
www.fisherregulators.com
289 Series
Specications
Available Congurations
See Table 1
Body Sizes and Inlet Connections
Type 289L: 3/4 or 1 NPT
Types 289A and 289U: 1/4 NPT
Type 289H: 1 or 2 NPT
Type 289HH: 1 NPT
Maximum Allowable Relief (Inlet) Pressure
Maximum Relief Set Pressure
See Table 1
Material Temperature Capabilities
Nitrile (NBR) and Neoprene (CR):
-20 to 150°F / -29 to 66°C
Fluorocarbon (FKM)
20 to 300°F / -7 to 149°C
Available with Types 289H and 289HH only
1. The pressure/temperature limits in this Instruction Manual and any applicable standard limitation should not be exceeded.
2. Bubble-tight shutoff cannot be attained at settings below 5 psig / 0.34 bar with Fluorocarbon (FKM) O-ring seat.
(2)
:
(1)
(1)
and
Pressure Setting Adjustment
Adjusting screw
Pressure Registration
Internal
Approximate Shipping Weights
Types 289A and 289U: 0.75 lbs / 0.3 kg
Type 289H:
1 NPT Size: 4 lbs / 2.0 kg
2 NPT Size: 15 lbs / 7.0 kg
Type 289HH: 4 lbs / 2.0 kg
Type 289L: 15 lbs / 7.0 kg
Additional Specications
For construction materials, see Parts List
Principle of Operation
Refer to Figures 2 and 4. The 289 Series Relief valves
are to be installed (between large service regulators
such as S202G or S302G Series) so the outlet is
piped downstream to relieve excess pressure to the
atmosphere. As inlet pressure increases, the spring
is compressed by the diaphragm, moving the disk
away from the seat. When the valve is opening, high
gas velocity through the orice creates an area of
relatively low pressure near the end of the pitot tube.
This pitot tube effect forms a partial vacuum above the
diaphragm (spring case area) which helps to open the
valve further.
Installation
WARNING
!
Installing a 289 Series relief valve where
its capabilities can be exceeded or where
proper operation might be impaired
may cause personal injury, property
damage or leakage due to bursting of
pressure-containing parts or explosion
of accumulated gas. To avoid such
conditions, install a 289 Series relief
valve where:
• Service conditions are within the
unit capabilities specied in the
Specications section and
• The relief valve is protected from
exposure to physical damage and/or
corrosive substances.
1. When installing a 289 Series relief valve, make sure
that the installation of the system complies with
applicable local, state or federal codes or regulations.
2. Use qualied personnel when installing, operating
and maintaining a 289 Series relief valve. Before
installation, make sure there is no damage to
or foreign material in the relief valve and that all
piping is clean and unobstructed.
3. For installation of Types 289H, 289HH and 289L
relief valves, the vent in the spring case must
remain plugged or undrilled in order for the pitot
tube to function properly.
4. The 289 Series relief valves may be installed in any
orientation. However, when installing the relief valve
at an outside location, adequate protection, such as
2
rain caps or elbow piping (see Figure 4), must be
attached to the outlet to keep the relief valve from
getting plugged or from collecting moisture, corrosive
chemicals or other foreign materials. If piping is to be
attached to the valve outlet, the following parts (if they
are connected to the valve outlet as shown in
Figures 6 through 10) must rst be removed: the
screen (key 9), the snap ring (key 13) and the gasket
(key 15). A typical installation of a 289 Series Relief
Valve is shown in Figure 4.
WARNING
!
If using a 289 Series relief valve on
hazardous or ammable gas service,
personal injury and property damage
could occur due to re or explosion of
vented gas that may have accumulated.
To prevent such injury or damage,
provide piping or tubing to vent the gas
to a safe, well-ventilated area. Also, when
venting a hazardous gas, the piping or
tubing should be located far enough
away from any buildings or windows so
to not create a further hazard and the
vent opening should be protected against
anything that could clog it.
289 Series
M1048
INLET PRESSURE
OUTLET PRESSURE
Figure 2. 2 NPT Type 289H Operational Schematic
5. Apply pipe compound to the male pipeline
threads only; do not apply pipe compound to
the internal body threads. Then install the
relief valve so that the ow through it will match
the direction arrow or marking cast on the
valve body.
When installing the molded diaphragm in the
289 Series Relief Valves, make sure the diaphragm
convolutions is installed in the down position as shown
in Figure 3.
Startup
Key numbers are shown in Figures 6 through 10.
With proper installation completed and system
equipment properly adjusted, close any vent valves
and slowly open the upstream shutoff valve while
using pressure gauges to monitor pressure.
Note
To ensure proper operation of the pitot
tube, if present, the spring case (key 2)
must be tightly sealed. It is recommended
that the gasket (key 15) be replaced
whenever the closing cap (key 14) is
Figure 3. Installation of Diaphragm
INSTALL
DIAPHRAGM
CONVOLUTION
DOWN
3
289 Series
SERVICE
REGULATOR
PROTECT VENT PIPE
WITH RAIN CAP
289 SERIES
RELIEF VALVE
AJ4698-C
A2404-1
Figure 4. Typical Installation
removed. Antiseizing sealant should be
applied to the adjusting screw (key 6)
threads on valves without closing caps.
If set pressure adjustment is necessary, monitor the
inlet pressure with a gauge during the adjustment
procedure. Remove the closing cap (key 14) or loosen
the hex nut (key 11) and turn the adjusting screw (key 6)
clockwise to increase or counterclockwise to decrease
the relief pressure setting.
For 2 NPT Type 289H relief valves, when changing from
one spring range to another, it is recommended that a
new spring case be used so that the travel stop drive
screw will be positioned correctly for the corresponding
spring range. Each spring range requires that the travel
stop drive screw be positioned appropriately in the
spring case to prevent setting the relief valve pressure
too high. The location of the travel stop drive screw for
each spring and spring range is shown in Figure 5.
Maintenance
Relief valve parts are subject to normal wear and
should be inspected periodically for maintenance.
The frequency of inspection and replacement of parts
depends upon the severity of service conditions.
This section contains information for inspection
and maintenance of 289 Series relief valves.
Maintenance procedures are presented for relief valve
congurations of similar construction. Refer to the
appropriate procedure and gure for the particular
relief valve conguration when changing the control
spring to one of a different range or when inspecting,
cleaning or replacing any other relief valve parts. The
screen (key 9, Figures 6 through 9) and vent piping, if
present, should be free of foreign material that might
impair relief ow.
Note
Shutdown
Close the upstream shutoff valve, and release all
pressure from the relief valve.
4
The relief valve body (key 1, Figures 6
through 10) may remain in the pipeline
during maintenance unless replacement
of the valve body is necessary.
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