Page 1
RABO® Rotary Gas Meter
Instruction Manual
Page 2
Page 3
1. General Information
This manual covers the installation, operation and maintenance
for the Elster Instromet RABO Rotary Meter. Refer to EAM-TB5900
for additional information.
2. Intended Use and Application
Elster RABO meters are suitable for measuring most types of
clean, dry, non-corrosive common gases. They are NOT intended
for use on biogas, sewage gas, oxygen, acetylene or liquids of
any kind. Product life and measurement accuracy can be affected
by contamination in the gas stream. Periodic servicing will prolong
the life and performance of the meter.
3. Operating Principle
The RABO meter utilizes positive displacement principle of
operation which makes volumetric measurements by displacing
finite volumes of gas. The positive displacement occurs within
a cavity formed between the meter’s internal housing and its
rotating impellers. The counter-rotating “figure-8” impellers [Figure
1] turn as a result of pressure drop across the meter’s inlet and
outlet created as downstream gas is consumed. The rotating
impellers separate the flowing gas into small, finite volumes
and are counted using a mechanical index. The RABO meter
has no wearing parts because precision clearances between
the impellers and meter body are maintained by timing gears,
which are designed to enhance long term accuracy. Combining
adequate filtration and periodic maintenance, a RABO meter will
remain accurate over many years.
Table of Contents
1. General Information 2
2. Intended Use and Application
2
3. Operating Principle
2
4. Receiving, Handling and Storage
3
5. Installation
3
6. Start-up/Commissioning
5
7. Decommissioning and Removal
5
8. Inspection and Maintenance
5
9. Testing
5
10. Technical Data
7
11. Index
8
12. Pulser 10
13. Thermowell 11
14. Auxiliary Equipment Mounting 11
15. Troubleshooting 11
RABO® Rotary Gas Meter
RABO® Rotary Gas Meter 02 Elster Instromet
RABO
®
Rotary Gas Meter
1. General Information 3
2. Intended Use and Application 3
3. Operating Principle 3
4. Receiving, Handling and Storage 4
5. Installation 4
6. Start-up/Commissioning 6
7. Decommissioning and Removal 6
8. Inspection and Maintenance 6
9. Testing 6
10. Technical Data 8
11. Index 9
12. Pulser 11
13. Thermowell 12
14. Instrument Drive (ID) 12
15. Auxiliary Equipment Mounting 14
16. Troubleshooting 15
Table of Contents
The RABO meter utilizes positive displacement principle of
operation which makes volumetric measurements by displacing
finite volumes of gas. The positive displacement occurs within
a cavity formed between the meter’s internal housing and its
rotating impellers. The counter-rotating “figure-8” impellers [Figu
re
1] turn as a result of pressure drop across the meter’s inlet and
outlet created as downstream gas is consumed. The rotating
impellers separate the flowing gas into small, finite volumes
and are counted using a mechanical index. The RABO meter
has no wearing parts because precision clearances between
the impellers and meter body are maintained by timing gears,
which are designed to enhance long term accuracy. Combining
adequate filtration and periodic maintenance, a RABO meter will
remain accurate over many years.
1. General Information
2. Intended Use and Application
3. Operating Principle
This manual covers the installation, operation and maintenance
for the Elster Instromet RABO Rotary Meter. Refer to EAM-TB5900
for additional information.
Elster RABO meters are suitable for measuring most types of
clean, dry, non-corrosive common gases. They are NOT intended
for use on biogas, sewage gas, oxygen, acetylene or liquids of
any kind. Product life and measurement accuracy can be affected
by contamination in the gas stream. Periodic servicing will prolong
the life and performance of the meter.
Figure 1. Operating Principle
As the left impeller rotates
toward the vertical position,
gas enters the cavity created
between the impeller
and the housing.
When the left impeller
reaches the vertical
position, a finite volume
of gas is captured in the
left cavity.
As the impellers continue
to turn, the volume of gas in
the left cavity is discharged.
Simultaneously, gas is
entering the space between
the right impeller and
housing.
After further rotation, the
right impeller becomes
vertical and a finite volume
of gas is captured in the
right cavity.
ELSTER RABO® Rotary Gas Meter 03 Honeywell
Page 4
ELSTER RABO® Rotary Gas Meter 04 Honeywell
RABO® Rotary Gas Meter 03 Elster Instromet
4. Receiving, Handling and Storage
Elster RABO meters should be handled with care to protect the
product from damage. If the package shows evidence of damage
through mishandling in transit, you should notify the shipper
immediately, file a claim with the carrier and notify your Elster
supplier.
Damage to internal components may occur without visible
external damage. All new meters should be inspected and
checked for free rotation of the impellers by lightly blowing
into the inlet of the meter. This slight air pressure should
cause the impellers to rotate freely and come to a stop slowly.
NOTICE
a) Piping Configurations [Figures 2, 3 and 4]
DO NOT weld piping while meter is installed in the
piping system.
If hydro testing, remove the meter from the piping system.
NOTICE
NOTICE
RABO® Rotary Gas Meter 03 Elster Instromet
4. Receiving, Handling and Storage
Elster RABO meters should be handled with care to protect the
product from damage. If the package shows evidence of damage
through mishandling in transit, you should notify the shipper
immediately, file a claim with the carrier and notify your Elster
supplier.
Damage to internal components may occur without visible
external damage. All new meters should be inspected and
checked for free rotation of the impellers by lightly blowing
into the inlet of the meter. This slight air pressure should
cause the impellers to rotate freely and come to a stop slowly.
NOTICE
a) Piping Configurations [Figures 2, 3 and 4]
DO NOT weld piping while meter is installed in the
piping system.
If hydro testing, remove the meter from the piping system.
NOTICE
NOTICE
RABO® Rotary Gas Meter 03 Elster Instromet
4. Receiving, Handling and Storage
Elster RABO meters should be handled with care to protect the
product from damage. If the package shows evidence of damage
through mishandling in transit, you should notify the shipper
immediately, file a claim with the carrier and notify your Elster
supplier.
Damage to internal components may occur without visible
external damage. All new meters should be inspected and
checked for free rotation of the impellers by lightly blowing
into the inlet of the meter. This slight air pressure should
cause the impellers to rotate freely and come to a stop slowly.
NOTICE
a) Piping Configurations [Figures 2, 3 and 4]
DO NOT weld piping while meter is installed in the
piping system.
If hydro testing, remove the meter from the piping system.
NOTICE
NOTICE
DO NOT weld piping while meter is installed in the
piping system.
If hydro testing, remove the meter from the piping system.
NOTICE
NOTICE
Figure 2. Horizontal installation, side view
a) Piping Configurations [Figures 2, 3 and 4]
DO NOT weld piping while meter is installed in the
piping system.
If hydro testing, remove the meter from the piping system.
NOTICE
NOTICE
4. Receiving, Handling and Storage
5. Installation
a) Piping Configurations [Figures 2, 3 and 4]
Figure 2. Horizontal installation, side view
Figure 3. Vertical installation, side view
Elster RABO meters should be handled with care to protect the
product from damage. If the package shows evidence of damage
through mishandling in transit, you should notify the shipper
immediately, file a claim with the carrier and notify your Elster
supplier.
Damage to internal components may occur without visible
external damage. All new meters should be inspected and
checked for free rotation of the impellers by lightly blowing
into the inlet of the meter. This slight air pressure should
cause the impellers to rotate freely and come to a stop slowly.
DO NOT attempt to make any repairs. Tampering with the
meter may void warranty coverage.
If a meter shows signs of external damage, or if the impellers do
not rotate freely, contact your local Elster sales representative for
return instructions.
Elster RABO meters are supplied with oil in a separate container.
A material safety data sheet (MSDS) is available upon request.DO
NOT put oil in the meter until it is installed and leveled in the gas
piping system. Meters containing oil that are transported or not
installed level may lead to contamination of the measurement
chamber, and will impact accuracy.
Store Elster RABO meters in their original shipping container in a
dry location until installation. If prolonged storage is experienced,
RABO meters should be tested for accuracy before installation.
Elster RABO meters can be installed in horizontal or vertical (top
inlet) piping configurations. Vertical (top inlet) piping is preferred
because it enables the meter to pass contaminants more freely
through the meter. All piping should be properly supported
and aligned to eliminate any strain on the meter, which may cau
se
the impellers to bind.
Recommended piping practices include a filter or strainer on the
inlet of the meter and non-lubricated isolation valves. A bypass
line will facilitate maintenance and removal of the meter and
provide uninterrupted gas supply.
The meter should not be installed lower than the outlet pipe run.
If it is necessary to install the meter lower than the outlet pipe run,
installation of a drip leg in the outlet piping to capture condensate
is recommended. The meter should never be located at the lowest
point in the system.
A restricting orifice can also be installed at least 4 pipe diameters
downstream of the outlet of the meter to prevent the meter from
flowing excess capacity. Warranty does not cover failures due to
excess flow conditions.
DO NOT weld piping while meter is installed in the
piping system.
If hydro testing, remove the meter from the piping system.
Page 5
ELSTER RABO® Rotary Gas Meter 05 Honeywell
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 4. Side view
applicable local codes and ordinances.
debris.
to installation.
nameplate.
must be horizontal [Figure 4].
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
tighten flange bolts evenly (maximum 80ft-lbs).
!
WARNING
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
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LEV EL
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OIL
DRA IN
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 4. Side view
applicable local codes and ordinances.
debris.
to installation.
nameplate.
must be horizontal [Figure 4].
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
tighten flange bolts evenly (maximum 80ft-lbs).
!
WARNING
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 4. Side view
applicable local codes and ordinances.
debris.
to installation.
nameplate.
must be horizontal [Figure 4].
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
tighten flange bolts evenly (maximum 80ft-lbs).
!
WARNING
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
Figure 5. Horizontal installation
Figure 6. Vertical installation
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
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FIL L
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LEV EL
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OIL
DRA IN
b) Mounting
c) Adding Oil
Figure 4. Side view
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 7. Sight glass
1) Always follow your company’s procedures, and
applicable local codes and ordinances.
2) Ensure gas valves are closed.
3) Ensure the upstream piping is clean and free of any
debris.
4) Remove protective caps from meter inlet and outlet prior
to installation.
5) Ensure the impellers turn freely.
6) Ensure the direction of flow using the arrow on the
nameplate.
7) Ensure the meter orientation is correct. Impeller shafts
must be horizontal [Figure 4].
8) Connect the inlet and outlet pipe flanges using
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
9) Level meter to within 1/16“ per foot in all directions and
tighten flange bolts evenly (maximum 80ft-lbs).
Add oil only to the index end of the meter.
1) Ensure gas valves are closed and meter and piping are
depressurized.
Failure to depressurize the meter prior to removing
meter and/or components could result in personal
injury and/or property damage.
2) Remove oil fill plug in the counter end case cover using a
5mm hex key [Figures 5 and 6].
3) Using the supplied syringe and oil, slowly add oil until
it is +/-1/16“ of the center of the sight glass [Figure 7].
DO NOT OVERFILL. Only use Shell Morlina lubricating oil.
DO NOT remove any sight glasses. No maintenance
can be performed through these openings.
4) Reinstall the oil fill plug.
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
Figure 5. Horizontal installation
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
Page 6
ELSTER RABO® Rotary Gas Meter 06 Honeywell
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 4. Side view
applicable local codes and ordinances.
debris.
to installation.
nameplate.
must be horizontal [Figure 4].
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
tighten flange bolts evenly (maximum 80ft-lbs).
!
WARNING
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
®
Rotary Gas Meter 05 Elster Instromet
7. Decommissioning and Removal
a) Always follow your company’s procedures, and local codes
and ordinances.
b) Slowly open bypass valve.
c) Slowly close the meter’s outlet valve, then the inlet valve.
d) Slowly, completely depressurize the meter piping.
!
WARNING
Failure to depressurize the meter prior to removing meter
and/or components could result in personal injury and/or
property damage.
e) Drain oil from the index end case cover and dispose of the oil
in accordance with applicable regulations.
f) If removing the meter from the piping system, loosen flange
bolts. Ensure meter is properly supported before removing
bolts completely.
8. Inspection and Maintenance
It is recommended to inspect Elster RABO meters periodically to
help ensure accurate performance over a long period of time.
Maintenance intervals can be derived from inspection criteria.
Routine inspections should include:
a) Checking to ensure the meter is level in all planes
b) Listening for abnormal sounds in the meter
c) Checking oil level and clarity — oil should be red and clear
d) Checking index movement if gas is flowing
e) Checking for leaks
f) Testing the meter’s differential pressure
Routine maintenance should include:
a) Changing the oil if the color becomes dark
will not be exceeded.
and ordinances.
bypass valve and pressurize the piping system.
inlet valve not to exceed 5 psig per second until pressure
is equalized throughout the meter piping system. Rapid
pressurization can cause an over-speed condition and
can damage the meter. Damage will not be covered
under warranty. When the meter piping system pressure is
stabilized, open the inlet valve completely.
operate at low speed. Meter speed can be seen through the
view port located on the back of the meter [Figure 8].
VIE W PORT
Figure 8. Back of meter
6. Start-up/Commissioning
7. Decommissioning and Removal
After the meter has been properly installed, it is important to use
extreme care during start-up to mitigate adverse conditions that
can damage the meter.
a) Ensure that the maximum operating pressure of the meter
will not be exceeded.
b) Always follow your company’s procedures, and local codes
and ordinances.
c) With the meter run’s inlet and outlet valves closed, open the
bypass valve and pressurize the piping system.
d) With the meter outlet valve closed, slowly open the meter
inlet valve not to exceed 5 psig per second until pressure
is equalized throughout the meter piping system. Rapid
pressurization can cause an over-speed condition and
can damage the meter. Damage will not be covered
under warranty. When the meter piping system pressure is
stabilized, open the inlet valve completely.
e) Slowly open the meter’s outlet valve until the meter starts to
operate at low speed. Meter speed can be seen through the
view port located on the back of the meter [Figure 8].
f) Operate the meter at low flow for 1 to 2 minutes to verify
proper operation. If the index does not start registration, or
if you hear knocking or scraping sounds coming from the
meter, stop the flow and follow appropriate decommissioning
procedures before removing the meter from the line.
g) If operation is satisfactory, gradually open the meter’s outlet
valve to the full open position.
h) Slowly close the bypass valve.
i) Check the meter connections for leaks using common
industry practices.
j) Clock the meter (see Index section 11c) to confirm the flow rate
is not exceeding the maximum capacity of the meter.
k) Perform and record the meter’s differential pressure (see
Testing section 9b).
8. Inspection and Maintenance
9. Testing
e) Drain oil from the index end case cover and dispose of the oil
in accordance with applicable regulations.
f) If removing the meter from the piping system, loosen flange
bolts. Ensure meter is properly supported before removing
bolts completely.
a) Always follow your company’s procedures, and local codes
and ordinances.
b) Slowly open bypass valve.
c) Slowly close the meter’s outlet valve, then the inlet valve.
d) Slowly, completely depressurize the meter piping.
Failure to depressurize the meter prior to removing meter
and/or components could result in personal injury and/or
property damage.
It is recommended to inspect Elster RABO meters periodically to
help ensure accurate performance over a long period of time.
Maintenance intervals can be derived from inspection criteria.
Routine inspections should include:
a) Checking to ensure the meter is level in all planes
b) Listening for abnormal sounds in the meter
c) Checking oil level and clarity — oil should be red and clear
d) Checking index movement if gas is flowing
e) Checking for leaks
f) Testing the meter’s differential pressure
Routine maintenance should include:
a) Changing the oil if the color becomes dark
b) Adding oil if the color is red and clear, but below the
recommended level
Elster RABO meters should be tested in accordance with applicable
governing standards. The accuracy of a meter can only be
determined by comparing results to a traceable reference, typically
a sonic nozzle, bell, piston or transfer prover. Accuracy may be
done on site using transfer provers, and typically requires removal
for testing with other technologies.
Differential pressure testing is a method of determining whether
the performance of a rotary meter may have changed over time,
and can be done on site while the meter is operating under
pressure. Baseline data must be captured during initial start-up to
which future data can be compared.
a) Proving
When testing a meter on a prover, the meter temperature,
pressure and volume are necessary inputs for the proving
device. The meter temperature is obtained by a temperature
probe installed near the inlet of the meter. A thermowell
can be installed in the meter run piping or on the meter
itself to facilitate installation of the temperature probe.
The meter pressure should come from the meter differential
pressure taps.
Page 7
ELSTER RABO® Rotary Gas Meter 07 Honeywell
Pete’s Plugs® are provided for simplified pressure connections
[Figure 9]. Typically, when proving a meter, both the meter
pressure and meter differential pressure are used and
recorded. The RABO meter differential pressure ports are not
full bore and most temperature probes will not fit through
into the gas stream. Installing the temperature probe in the
provided thermowell ports is recommended.
b) Differential Pressure Testing
A differential pressure test is not an accuracy test, but it can
be used to gauge the relative performance of the meter.
Rotary meters are made from solid parts, machined to tight
tolerances with close clearance fits, and the energy it takes
to turn the meter is generally used to overcome the friction
of the bearings and other rotating parts. If this friction value
increases, it will take more energy to overcome it. This
additional energy is measured as an increased pressure
drop across the meter.
The increased friction is caused by contamination of the
measuring chamber and/or bearings.
Contamination in the measuring chamber can cause the
meter components to wear against each other. Contamination
in the bearings makes them harder to turn.
Comparing the pressure drop reading when the meter is new
to the reading collected after time allows the performance to
be monitored.
RABO meters are supplied with Pete’s Plugs
®
installed in the
meter differential pressure ports [Figure 9]. This facilitates
differential meter testing. A differential pressure test is
performed using a differential pressure manometer. The test
PET E’S PLUGS
®
RABO® Rotary Gas Meter 06 Elster Instromet
Figure 9. Pressure test ports
Pressure test ports are provided for simplified pressure
connections [Figure 9].
Below 45
O
F the neoprene core of the Pressure test ports
does not recover its original shape as rapidly as it would
at temperatures above 45
O
F. Therefore, upon removal of
the probe used for pressure or temperature readings, the
valves may not close fully and immediately or the valves
may remain slightly open until the operating temperature
is above 45
O
F. Duration of probe insertion and pressure
are also factors in the rate of valve closing. For this reason,
plugs should not be used in applications where discharging
gas or liquids would create a hazard. The gasketed cap
is supplied to eliminate the small amount of leakage that
may occur at lower temperatures after probe insertion and
removal. The cap should be left on the plug at all times
and tightened to deter unauthorized removal. Special care
should be taken to assure that readings are taken in the
shortest space of time and that a probe is never left in a
plug for a period of hours or days. Severe deformation of
the valves may occur if the probe is left in the plug for a
long period of time.
b) Differential Pressure Testing
Typically, when proving a meter, both the meter pressure and
meter differential pressure are used and recorded. The RABO
meter differential pressure ports are not full bore and most
temperature probes will not fit through into the gas stream.
Installing the temperature probe in the provided thermowell
ports is recommended.
The meter volume is determined though a device that senses
the meter revolutions. An optical pickup can be used on the
index proving wheel or an index pulser may be used.
On-site proving, performed in-line, also requires connections
that allow air flow through the meter to the prover. This is
accomplished by use of pipe Tees upstream and downstream
of the meter. A bypass loop is recommended for uninterrupted
gas supply to the customer.
A differential pressure test is not an accuracy test, but it can
be used to gauge the relative performance of the meter.
Rotary meters are made from solid parts, machined to tight
tolerances with close clearance fits, and the energy it takes
to turn the meter is generally used to overcome the friction
of the bearings and other rotating parts. If this friction value
increases, it will take more energy to overcome it. This
additional energy is measured as an increased pressure
drop across the meter.
The increased friction is caused by contamination of the
measuring chamber and/or bearings.
Contamination in the measuring chamber can cause the
meter components to wear against each other. Contamination
in the bearings makes them harder to turn.
Comparing the pressure drop reading when the meter is new
to the reading collected after time allows the performance to
be monitored.
RABO meters are supplied with Pressure test ports
installed
in the meter differential pressure ports [Figure 9]. This facilitates differential meter testing. A differential pressure test is
performed using a differential pressure manometer. The test
is to measure the pressure drop across the meter at a given
flow rate, under known operating conditions at a known date
and time.
The meter differential curve of flow rate vs pressure is not
linear. Testing at multiple flow rates is suggested. It is
preferable to test at 3 rates between 25% and 100% of flow
if possible. Differential pressure tests at flow rates under
25% are hard to interpret because the meter differential
pressure at the lower flow rates is quite small. The errorin
measurement is almost as large as the reading itself.
The meter differential pressure is also a function of line
pressure and increases as line pressure increases. Testing
the meter at the same conditions (line pressure and flow
rates) yields comparable data.
A change in the differential pressure indicates a change
in performance. Testing has shown that a 50% increase in
meter differential pressure (at flow rates over 25%), indicates
almost a 1.0% change in meter accuracy.
Baseline data must be captured during initial start-up to
which future data can be compared.
If the differential pressure test shows an increase in the meter
pressure drop at a given flow rate of more than 50% from the
original value (1.5 x original value), then it is recommended
that the meter be removed and serviced.
The frequency of deferential testing is at the discretion of
the user.
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 4. Side view
applicable local codes and ordinances.
debris.
to installation.
nameplate.
must be horizontal [Figure 4].
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
tighten flange bolts evenly (maximum 80ft-lbs).
!
WARNING
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
While performing an accuracy test, the meter is tested for
a specified volume of gas at each flow rate test point. Poor
repeatability at a given rate may be caused by a test volume
that is too small. It the meter does not repeat within acceptable
limits (0.1%), try increasing the test volume and retesting
the meter. Most companies have developed test plans
that include the volume of gas for each size meter at a
given flow rate. Consult your Elster representative for
applicable volumes.
PRESSURE TEST PORTS
Page 8
ELSTER RABO® Rotary Gas Meter 08 Honeywell
10. Technical Data
a) Performance
b) Sizing Chart
Using the chart below, select the appropriate meter by using the Maximum Instantaneous Flow Rate (scfh) and the Minimum
Operating Pressure (psig) at any given point in time.
Example: A flow rate of 25,000 scfh and an operating pressure range of 75–100 psig would require a 5.5M meter based on a
75 psig minimum inlet pressure.
Rangeability
Start Rate
Stop Rate
Flow Rate at ½“ w.c. DP, Gas
Differential Pressure at 100% Flow Rate
Units
acfh [am
3
/h]
acfh [am
3
/h]
acfh [am
3
/h]
in.w.c.
[mBar]
3.5M/G65
90:1
1.3
1.1
2,715
1.46
[0.04]
[0.03]
[77]
[3.64]
14M/G250
160:1
2.5
2.3
6,740
2.65
[0.07]
[0.07]
[191]
[6.60]
5.5M/G100
160:1
0.9
0.8
4,074
1.23
[0.03]
[0.02]
[115]
[3.06]
9M/G160
160:1
2.5
1.9
5,722
1.70
[0.07]
[0.05]
[162]
[4.23]
Model 3.5M/G65
5.5M/G100
9M/G160
14M/G250
psig [Barg
]
0.25
2
5
10
20
30
40
50
60
75
100
150
175
250
290
[0.0]
[0.1]
[0.3]
[0.7]
[1.4]
[2.1]
[2.8]
[3.4]
[4.1]
[5.2]
[6.9]
[10.3]
[12.1]
[17.2]
[20.0]
[100]
[110]
[130]
[160]
[230]
[300]
[370]
[430]
[500]
[600]
[770]
[1,110]
[1,270]
[1,780]
[2,050]
3,500
3,900
4,600
5,800
8,200
10,500
12,900
15,300
17,700
21,200
27,200
39,100
45,000
62,800
72,300
5,500
6,100
7,200
9,100
12,800
16,600
20,300
24,000
27,800
33,400
42,700
61,400
70,700
98,700
113,700
[160]
[170]
[200]
[260]
[360]
[470]
[570]
[680]
[790]
[950]
[1,210]
[1,740]
[2,000]
[2,790]
[3,220]
9,000
10,000
11,900
14,900
21,000
27,100
33,200
39,300
45,500
54,600
69,900
100,400
115,700
161,500
186,000
[250]
[280]
[340]
[420]
[590]
[770]
[940]
[1,110]
[1,
290]
[1,550]
[1,980]
[2,840]
[3,280]
[4,570]
[5,270]
Corrected Capacity in scfh [sm3/h]
14,000
15,600
18,400
23,200
32,700
42,200
51,700
61,200
70,700
85,000
108,700
156,300
180,000
251,300
289,300
[400]
[440]
[520]
[660]
[930]
[1,190]
[1,46
0]
[1,730]
[2,00
0]
[2,410]
[3,080]
[4,430]
[5,100]
[7,120]
[8,190]
Note: All capacities based on 14.4 psia atmospheric pressure, 14.73 psia base pressure, and 60
O
F base temperature.
Note: Values are for air, except Flow Rate at
½“ w.c. DP, which are natural gas values.
Page 9
ELSTER RABO® Rotary Gas Meter 09 Honeywell
Units 3.5M/G65 5.5M/G100 9M/G160 14M/G250
A
in. [mm] 6.75 [171] 6.75 [171] 9.5 [241] 9.5 [241]
B
in. [mm] 7.56 [192] 7.56 [192] 10.08 [256] 10.08 [256]
C
in. [mm] 8.63 [219] 8.63 [219] 10.75 [273] 10.75 [273]
D
in. [mm] 3.78 [96] 5.43 [138] 5.16 [131] 6.14 [156]
E
in. [mm] 7.52 [191] 9.17 [233] 10.67 [271] 11.65 [296]
F
in. [mm] 11.26 [286] 14.61 [371] 15.83 [402] 17.76 [451]
G
in. [mm] 3.78 [96] 3.78 [96] 5.04 [128] 5.04 [128]
Nom. Pipe Size
*
in. [mm] 2 3 3 4
Bolt Size, H
5/8" - 11 5/8" - 11 5/8" - 11 5/8" - 11
# Bolts/Flange
4 4 4 8
Bolt Circle, J
in. [mm] 4.75 [121] 6.00 [152] 6.00 [152] 7.50 [191]
Shipping Weight
lbs. [kg] 29.8 [14] 37.7 [17] 73.9 [34] 82.3 [37]
Carton Size
in. 18.3L x 1.6W x 12.6H 23.6L x 13.0W x 13.4H
[mm] 465L x 270W x 320H 600L x 330W x 340H
c) Dimensions and Weights
*ANSI Class 125/150 flat face flange connection
F
D
E
H
J
A
B
C
2.36
60
2.36
60
M6x1
RABO® Rotary Gas Meter 08 Elster Instromet
c) Dimensions and Weights
b) How to Read
11. Index
*ANSI Class 125/150 flat face flange connection
A
B
C
D
E
F
G
Nom. Pipe Size*
Bolt Size, H
# Bolts/Flange
Bolt Circle, J
Shipping Weight
Carton Size
in. [mm]
in. [mm]
in. [mm]
in. [mm]
in. [mm]
in. [mm]
in. [mm]
in. [mm]
in. [mm]
Ibs. [kg]
in.
[mm]
Units
6.75
7.56
8.63
3.78
7.52
11.26
3.78
[171]
[192]
[219]
[96]
[191]
[286]
[96]
6.75
7.56
8.63
5.43
9.17
14.61
3.78
[171]
[192]
[219]
[138]
[233]
[371]
[96]
9.5
10.08
10.75
5.16
10.67
15.83
5.04
[241]
[256]
[273]
[131]
[271]
[402]
[128]
9.5
10.08
10.75
6.14
11.65
17.76
5.04
[241]
[256]
[273]
[156]
[296]
[451]
[128]
4
332
5/8“ - 11
5/8“ - 11 5/8“ - 11
5/8“ - 11
4 4
4
8
18.3L x 10.6W x 12.6H
465L x 270W x 320H
23.6L x 13.0W x 13.4H
600L x 330W x 340H
4.75
29.8
6.00
37.7
6.00
73.9
7.50
82.3
[121]
[14]
[152]
[17]
[152]
[34]
[191]
[37]
All RABO meters are equipped with a non-resettable totalizing
odometer-style index that displays volume in actual cubic feet. The
index is sealed by an ultraviolet-resistant Lexan cover, requires no
maintenance and is completely isolated from gas pressure.
The RABO index can rotate 355 degrees to facilitate desired
reading angle, depending on the installation orientation. To
rotate, simply grasp the index with both hands and turn to the
desired position.
b) Rotatable
The odometer index is masked to expose the desired digits
and units of measure to meet individual requirements.
On all meters, the right-most digit will be highlighted
with a red square on the index mask, and will always
increment in cubic feet. This digit is typically not included in
the meter read and is primarily used to indicate flow rate.
When reading an odometer, record all the digits except the
digit surrounded by the red square on the index mask, and
multiply it by the factor shown on the index face plate. In the
example on the next page, the reading would be 1357900
cubic feet.[Figure 10].
3.5M/G65
5.5M/G100
9M/G160
14M/G250
Page 10
ELSTER RABO® Rotary Gas Meter 10 Honeywell
RABO® Rotary Gas Meter 09 Elster Instromet
3. Pull off the index cover.
• It helps to rock it slightly.
• Be careful not to damage the masking plate and
index when removing the cover.
4. Carefully pull off the index masking plate [Figure 12].
RABO® Rotary Gas Meter 09 Elster Instromet
3. Pull off the index cover.
• It helps to rock it slightly.
• Be careful not to damage the masking plate and
index when removing the cover.
4. Carefully pull off the index masking plate [Figure 12].
Figure 10. Index
Figure 12. Index masking plate
c) How to “Clock” a Meter
The odometer index can be used to calculate the instantaneous
flow rate by using the right-most digit (test dial). Each number
on this dial represents one (1) cubic foot, and one complete
revolution of this dial represents ten (10) cubic feet. You will
need a stop watch or a watch with a sweep second hand to
calculate flow rate.
1. Measure the time, in seconds, that it takes the test dial to
make one complete revolution (10 cubic feet).
2. Use the following formula to calculate flow rate:
Flow Rate (acfh) = (10 ÷ “time”) x 3600
Note that the odometer index does not compensate for
elevated pressure or temperature. Correction factors will
need to be applied to adjust the ow rate to standard
conditions (scfh)
.
d) Removal, Installation and Replacement
Steps to replace the RABO meter index:
1. Cut the seal wires and remove from the holes [Figure 11].
2. Remove (unscrew) the two brass screws on the sides of
the index cover [Figure 11].
5. Remove the three index retaining screws using a Torx
T20 driver [Figure 13].
Figure 13. Index retaining screws
IND EX
RETAI NING
SCR EW
IND EX
RETAI NING
SCR EW
IND EX
RETAI NING
SCR EW
SEA LS
6. Carefully remove the index.
• Pay attention to the driven magnet — it is supported
by the index.
• Leave the magnet on the meter.
7. Transfer the change gear from the damaged index to the
replacement [Figures 14 and 15].
• Remove the change gear on the damaged index.
• Pry the locking collar off with a knife blade or other
sharp object.
• Unscrew the change gear.
!
WARNING
Each meter size uses a common index that has
unique colored gears. Interchanging colored
gears will result in inaccurate readings. Ensure
the replacement index has the same color gears.
[Refer to Table 1]
• If the replacement index has a change gear, remove
SUP PORT
HOL E
3. Pull off the index cover.
• It helps to rock it slightly.
• Be careful not to damage the masking plate and
index when removing the cover.
4. Carefully pull off the index masking plate [Figure 12].
3. Pull off the index cover.
• It helps to rock it slightly.
• Be careful not to damage the masking plate and
index when removing the cover.
4. Carefully pull off the index masking plate [Figure 12].
Figure 12. Index masking plate
5. Remove the three index retaining screws using a Torx
T20 driver [Figure 13].
IND EX
RETAI NING
SCR EW
IND EX
RETAI NING
SCR EW
IND EX
RETAI NING
SCR EW
SUP PORT
HOL E
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 4. Side view
applicable local codes and ordinances.
debris.
to installation.
nameplate.
must be horizontal [Figure 4].
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
tighten flange bolts evenly (maximum 80ft-lbs).
!
WARNING
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
c) How to “Clock” a Meter
d) Removal, Installation and Replacement
Figure 10. Index
Figure 11. Index cover seals
Figure 12. Index masking plate
Figure 13. Index retaining screws
The odometer index can be used to calculate the instantaneous
flow rate by using the right-most digit (test dial). Each number
on this dial represents one (1) cubic foot, and one complete
revolution of this dial represents ten (10) cubic feet. You will
need a stop watch or a watch with a sweep second hand to
calculate flow rate.
1. Measure the time, in seconds, that it takes the test dial to
make one complete revolution (10 cubic feet).
2. Use the following formula to calculate flow rate:
Flow Rate (acfh) = (10 ÷ “time”) x 3600
Note that the odometer index does not compensate for
elevated pressure or temperature. Correction factors will
need to be applied to adjust the flow rate to standard
conditions (scfh).
Steps to replace the RABO meter index:
1. Cut the seal wires and remove from the holes [Figure 11].
2. Remove (unscrew) the two brass screws on the sides of
the index cover [Figure 11].
3. Pull off the index cover.
• It helps to rock it slightly.
• Be careful not to damage the masking plate and
index when removing the cover.
4. Carefully pull off the index masking plate [Figure 12].
5. Remove the three index retaining screws using a Torx
T20 driver [Figure 13].
6. Carefully remove the index.
• Pay attention to the driven magnet — it is supported
by the index.
• Leave the magnet on the meter.
7. Transfer the change gear from the damaged index to the
replacement [Figures 14 and 15].
• Remove the change gear on the damaged index.
• Pry the locking collar off with a knife blade or other
sharp object.
• Unscrew the change gear.
• If the replacement index has a change gear, remove
and discard it.
• Attach the change gear from the damaged index to
the same shaft on the replacement index.
• Secure gear on shaft.
• Snap on the locking collar.
Each meter size uses a common index that has
unique colored gears. Interchanging colored
gears will result in inaccurate readings. Ensure
the replacement index has the same color gears.
[Refer to Table 1]
Page 11
ELSTER RABO® Rotary Gas Meter 11 Honeywell
LOC KING COLL AR
CHA NGE GEAR
SUP PORT HOLE
®
Rotary Gas Meter 10 Elster Instromet
WHITE
1.E1
Technical Specifications
Description Min. Typ. Max. Unit
Voltage (U) 24
V
Current (I) 76 mA
Power (P) 1.1
W
Static Contact Resistance 200 mΩ
Insulation Resistance 10
9
Ω
Breakdown Voltage 100 100 VDC
Switching Time Including Bounce 0.5 ms
Release Time 0.1 ms
Temperature range: -40°C … +70°C
IP-Class: IP67
Explosion protection:
II 2 G EEx ia 2C T4
Figure 16. IN-S10 pulser installed
LOC KING COLL AR
CHA NGE GEAR
IND EX
Meter Gear Color
3.5M/G65 White
5.5M/G100 Dark Green
9M/G160 Green
14M/G250
Red
Table 1
LOC KING COLL AR
CHA NGE GEAR
SUP PORT HOLE
SUP PORT HOLE
Figure 14. Change gear removal
®
Rotary Gas Meter 10 Elster Instromet
Technical Specifications
Description Min. Typ. Max. Unit
Voltage (U) 24
V
Current (I) 76 mA
Power (P) 1.1
W
Static Contact Resistance 200 mΩ
Insulation Resistance 10
9
Ω
Breakdown Voltage 100 100 VDC
Switching Time Including Bounce 0.5 ms
Release Time 0.1 ms
Temperature range: -40°C … +70°C
IP-Class: IP67
Explosion protection:
II 2 G EEx ia 2C T4
Figure 16. IN-S10 pulser installed
Figure 5. Horizontal installation
Figure 6. Vertical installation
Figure 4. Side view
applicable local codes and ordinances.
debris.
to installation.
nameplate.
must be horizontal [Figure 4].
appropriate bolts and gaskets. Inlet and outlet pipe
flanges should be parallel and should not introduce any
bind on the meter body when tightened.
tighten flange bolts evenly (maximum 80ft-lbs).
!
WARNING
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
OIL
FIL L
OIL
FIL L
OIL
FIL L
OIL
LEV EL
SIG HT
GLA SS
OIL
DRA IN
Figure 14. Change gear removal
Figure 15. Index, change gear and locking collar
Figure 16. IN-S10 pulser installed
Figure 17. Pulser connections
Table 1
Meter Gear Color
3.5M/G65
5.5M/G100
9M/G160
14M/G250
White
Dark Green
Green
Red
12. Pulser
8. Install the replacement index.
• Orient the index so the mounting holes line up with
the posts in the base plate.
• Carefully ensure the shaft on the magnet holder is in
the support hole on the index frame [Figure 13].
• Install the three screws to retain the index to the base
plate. Tighten to snug.
9. Install index masking plate.
10. Install index cover.
11. Install security seals.
All RABO meter indexes can be easily outfitted with a pulse output
device to interface with auxiliary equipment. Installation of a
pulser is quick and easy, and requires no disassembly. To install
a pulser, simply slide the pulser into the slot on the index cover
[Figure 16], and connect the wires to the desired auxiliary devices
[Figure 17]. The pulser can be secured to the index cover screw with
a seal wire to mitigate and indicate tampering.
Explosion Hazard
Auxiliary equipment and interconnecting wiring must be in
accordance with local and national codes for hazardous areas.
Pulser Pin-Out Connections
Connector
1.E1
Pulse
Out 1
2.E1
Pulse
Out 2
PCM
Tamper
Circuit
IN-S11 1 + 2 5 + 6 3 + 4
IN-S12
1 + 2
(Back)
1 + 2
(Front)
3 + 4
(Front)
WHITE
BROWN
GREEN
YELLOW
GREY
PINK
1.E1
2.E1
PCM
V
W
9
Ω
II 2 G EEx ia 2C T4
1
2
3
4
5 6
(Ui)
(Ii)
(Pi)
V
I
25
V
I
0,25
V
I
II 2 G Ex ia IIC T4 Gb
WHITE
BROWN
GREEN
YELLOW
GREY
PINK
1.E1
2.E1
PCM
V
W
9
Ω
IN-S10
IN-S10A
Page 12
ELSTER RABO® Rotary Gas Meter 12 Honeywell
RABO® Rotary Gas Meter 11 Elster Instromet
ACC ESSO RY
Figure 19. Horizontal installation
14. Auxiliary Equipment Mounting
All RABO meters are equipped with threaded holes for mounting
compact, lightweight auxiliary equipment [Figures 19 and 20].
All holes are M6 x 1 by 10mm deep. Heavier equipment should
be pipe or wall mounted adjacent to the meter. Elster provides
customized brackets for commonly used equipment [Figure 21].
Please contact your local Elster representative for details.
NPT AUXI LIAR Y POR TS
Figure 20. Vertical installation
13. Thermowell
All RABO meters come equipped with two (2) ¼" NPT auxiliary
ports on the meter body [Figure 18], which can be used for sensing
pressure and temperature of the flowing gas. A thermowell is
required when using a temperature sensing device. Thermowells
are available as accessories to the meter.
ACC ESSO RY
Figure 18. Auxiliary ports
13. Thermowell
All RABO meters come equipped with two (2) ¼“ NPT auxiliary
ports on the meter body [Figure 18], which can be used for sensing
pressure and temperature of the flowing gas. A thermowell is
required when using a temperature sensing device. Thermowells
are available as accessories to the meter.
a) Installing a Thermowell
1. If meter is not installed in the gas piping, go to Step 5.
2. Slowly open bypass valve.
3. Slowly close the meter’s outlet valve, then the inlet valve.
4. Slowly, completely depressurize the meter piping.
5. Remove one of the plugs in the meter body by using a
¼“ hex key.
6. Apply Teflon tape or pipe dope to the male threads of the
thermowell. Wipe excess pipe dope off the thermowell
probe and leading threads to ensure no pipe dope
enters the metering chamber.
7. Screw the thermowell into the meter and tighten to
18 ft-lbs.
8. Re-pressurize the meter as instructed in Start-up/
Commissioning (see section 6).
14. Instrument Drive (ID)
RABO meters (3.5M/G65 and 5.5M/G100) can be retrofitted with
an instrument drive, or instrument adaptor plate. The ID provides a
mounting surface for instruments requiring mechanical rotational
input. The drive rate of the RABO ID is 10 cubic feet per 1 revolution
in a clockwise direction. When installing an instrument, orient
the instrument face to the FRONT edge of the adaptor plate. The
threads in the adaptor plate for instrument mounting are 5/16“ - 18.
a) Retrofit a CTR (CTR = Uncorrected Mechanical Totalizer) meter
with an Instrument Drive (ID).
i) Remove index. See section 11. d) 1 to 11. d) 6
ii) Transfer the change gear from the CTR index to the ID
gearing and index assembly [Figure 14 and 20].
(1) Pry the change gear’s locking collar off with
a knife blade or other similar object.
(2) Unscrew the change gear from the CTR index.
(3) Attach the change gear to the middle gear on the back
side of the ID gearing and index assembly.
(4) Reinstall locking collar to retain the change gear.
iii) Remove the magnet holder assembly from the meter
[Figure 21].
Figure 19. RABO with Instrument Drive
Figure 20. Change gear installation on ID gearing and index
assembly
CHANGE
GEAR
LOCKING
COLLAR
Figure 21. Magnet holder
MAGNET
HOLDER
ASSEMBLY
Page 13
ELSTER RABO® Rotary Gas Meter 13 Honeywell
iv) Unscrew the lock nut from the magnet holder
(THREADS ARE LEFT HAND) [Figure 17].
v) Unscrew the change gear from the magnet holder
(THREADS ARE LEFT HAND) [Figure 22].
vi) Assemble the change gear to the ID magnet holder
(THREADS ARE LEFT HAND).
(1) For 3.5M meters
(a) Apply Loctite
®
770 primer to the threads and mating
surfaces of the change gear and the magnet holder
[Figure 23]. Allow to dry for 30 seconds.
Figure 22. Magnet holder, change gear, and lock nut
CHANGE
GEAR
MAGNET
HOLDER
LOCK
NUT
Figure 23. Magnet holder and change gear adhesive application
for 3.5M meter.
APPLY LOCTITE
®
PRIMER
APPLY LOCTITE
®
PRIMER. APPLY
CA
(b) Apply Loctite
®
406, Loctite
®
495, or equivalent
Cyanoacrylate adhesive to the threads and mating
surface of the magnet holder [Figure 23]. Do not get
the adhesive on the small tip of the magnet holder.
(c) Quickly screw the change gear to the magnet holder
(THREADS ARE LEFT HAND) and tighten until gear
is snugly seated against magnet holder. Let dry
completely
(d) Do not reinstall the locknut for a 3.5M meter.
(2) For 5.5M meters
(a) Screw the change gear to the magnet holder
(THREADS ARE LEFT HAND) and tighten until gear is
snugly seated against magnet holder.
(b) Reinstall the lock nut (THREADS ARE LEFT HAND)
removed in a previous step. Tighten until snug.
vii) Install the ID magnet holder onto the end of the meter.
viii) Install the ID gearing and index assembly on meter.
(1) Orient the ID gearing and index assembly so the
mounting screws line up with the posts in the index
base plate.
(2) Ensure the shaft on the magnet holder aligns with
the support hole on the index frame [Figure 24].
Figure 24.
ID retaining screws
INDEX
RETAINING
SCREW
SUPPORT
HOLE (ON
BACK SIDE)
INDEX
RETAINING
SCREW
INDEX
RETAINING
SCREW
(3) Tighten the three screws until snug. Do not overtighten.
(a) Each screw should have a 2mm thick retaining
washer to space the ID gearing and index assembly
away from the base plate [Figure 25]. The spacers
are installed at the factory. Verify they have not
fallen off.
Figure 25.
Retaining washers
RETAINING
WASHER
ix) Check for binds
(1) Using compressed air blown into the meter inlet port,
confirm the index and ID output shaft rotate freely.
x) Snap the ID index masking plate onto three posts
of the index.
xi) Install the ID index cover.
(1) Lightly lubricate the blue or purple o-ring on the index
base plate with silicone o-ring grease.
(a) Do not use petroleum based lubricants
on this o-ring.
(2) Place the ID index cover onto the index base plate while
aligning the holes on the side of the index cover with the
holes in the index base plate.
(3) Install the brass index cover mounting screws which
were removed in a previous step. Tighten the screws just
until the screw head contacts the cover, then back the
screw out until the seal wire holes align.
xii) Attach the support bracket to the accessory mount holes in
the meter case cover [Figure 19, 26].
(1) The ID can be attached to a meter installed for horizontal
or vertical flow. Use the appropriate accessory mount
holes.
NOTE: Regardless the meter orientation installation, the
ID adaptor plate must be mounted horizontally
during operation so that the ID mounted accessory is in
a vertical orientation.
Page 14
RABO® Rotary Gas Meter 11 Elster Instromet
ACC ESSO RY
Problem Probable Cause Suggested Action
Excessive vibration Build-up of foreign material on impellers Clean by flushing, or replace worn parts
Misalignment Level meter in piping
Worn bearings Replace bearings
Worn timing gears Replace timing gears
Impellers contacting body Rotate manually to verify impellers spin freely
High differential pressure Heavyweight or too much oil Check oil level and condition
Dirt deposits on impellers Remove dirt by flushing
Impellers out of time Retime impellers
Impellers contacting body Rotate manually to verify impellers spin freely
Low registration Upstream or bypass leak Check all valves for leakage
Non-registration Broken or binding index odometer Replace odometer
Obstruction in meter Remove meter, remove obstructions, flush meter
15. Troubleshooting
Figure 19. Horizontal installation
14. Auxiliary Equipment Mounting
All RABO meters are equipped with threaded holes for mounting
compact, lightweight auxiliary equipment [Figures 19 and 20].
All holes are M6 x 1 by 10mm deep. Heavier equipment should
be pipe or wall mounted adjacent to the meter. Elster provides
customized brackets for commonly used equipment [Figure 21].
Please contact your local Elster representative for details.
NPT AUXI LIAR Y POR TS
Figure 18. Auxiliary ports
Figure 20. Vertical installation
13. Thermowell
All RABO meters come equipped with two (2) ¼" NPT auxiliary
ports on the meter body [Figure 18], which can be used for sensing
pressure and temperature of the flowing gas. A thermowell is
required when using a temperature sensing device. Thermowells
are available as accessories to the meter.
a) Installing a Thermowell
1. If meter is not installed in the gas piping, go to Step 5.
2. Slowly open bypass valve.
3. Slowly close the meter’s outlet valve, then the inlet valve.
4. Slowly, completely depressurize the meter piping.
5. Remove one of the plugs in the meter body by using a
¼" hex key.
6. Apply Teflon tape or pipe dope to the male threads of the
thermowell. Wipe excess pipe dope off the thermowell
probe and leading threads to ensure no pipe dope
enters the metering chamber.
7. Screw the thermowell into the meter and tighten to
18 ft-lbs.
8. Re-pressurize the meter as instructed in Start-up/
Commissioning (see section 6).
Figure 21. Auxilary equipment mounted
ACC ESSO RY
ELSTER RABO® Rotary Gas Meter 14 Honeywell
ACC ESSOR Y
14. Auxiliary Equipment Mounting
All RABO meters are equipped with threaded holes for mounting
compact, lightweight auxiliary equipment [Figures 19 and 20].
All holes are M6 x 1 by 10mm deep. Heavier equipment should
be pipe or wall mounted adjacent to the meter. Elster provides
customized brackets for commonly used equipment [Figure 21].
Please contact your local Elster representative for details.
ACC ESSOR Y
Figure 19. Horizontal installation
14. Auxiliary Equipment Mounting
All RABO meters are equipped with threaded holes for mounting
compact, lightweight auxiliary equipment [Figures 19 and 20].
All holes are M6 x 1 by 10mm deep. Heavier equipment should
be pipe or wall mounted adjacent to the meter. Elster provides
customized brackets for commonly used equipment [Figure 21].
Please contact your local Elster representative for details.
Figure 20. Vertical installation
ACC ESSO RY
Figure 32. Auxilary equipment mounted
Figure 30. Horizontal installation Figure 31. Vertical installation
15. Auxiliary Equipment Mounting
All RABO meters are equipped with threaded holes for mounting
compact, lightweight auxiliary equipment [Figures 30 and 31].
All holes are M6 x 1 by 10mm deep. Heavier equipment should
be pipe or wall mounted adjacent to the meter. Elster provides
customized brackets for commonly used equipment [Figure 32].
Please contact your local Elster representative for details.
Figure 26.
Support bracket attachment
3.5M-5.5M
Horizontal Flow
3.5M-5.5M
Vertical Flow
(2) Using a 5mm Allen wrench, loosely install two M6 socket
head cap screws through the support bracket into the
meter case cover [Figure 26]. The screws will be
tightened after alignment of all parts.
xiii) Install the adaptor plate assembly
(1) Lubricate the adaptor plate assembly o-ring with silicone
o-ring grease, light machine oil or petroleum jelly.
(2) Carefully align the slot of the output shaft to the flat of the
ID index output [Figure 27].
ID OUTPUT
OUTPUT
SHAFT
SLOT
(3) Fully insert the adaptor plate assembly post into the
index cover output hole.
(4) Orient the adaptor plate to the desired direction
(4 positions are possible: Facing away from the meter,
facing the meter, facing the meter inlet, or facing
the meter outlet).
xiv) Using a 5mm Allen wrench, install two M6 socket head
cap screws through the adaptor plate into the support
bracket assembled in a previous step [Figure 28]. Tighten
to 45-50 in-lbs.
Figure 27.
Figure 28.
SOCKET HEAD
CAP SCREWS
xv) Using a 3mm Allen wrench, install two set screws through
the index cover neck to secure the adaptor plate assembly
[Figure 29]. Tighten snuggly.
Figure 29. Set screw installation
SET SCREWS
xvi) Tighten the two M6 socket head cap screws installed earlier
(to affix the support bracket to the meter case cover)
to 45-50 in-lbs.
xvii) Install security seals as required.
(1) Security wires are included to secure the index cover
mounting screws and the support bracket lower
mounting screws.
(a) To install, feed the security wire through the holes in
the drilled head screws, thread the free end of the
wire through the hole in the center of the seal, pull
tight, and snap the seal together.
(2) Red Security seals (plugs) are included to seal the support
bracket upper mounting screws.
(a) To install, press the seals in the adaptor plate holes
over the screws until they are fully seated.
ACC ESSOR Y
Page 15
RABO® Rotary Gas Meter 11 Elster Instromet
ACC ESSO RY
Problem Probable Cause Suggested Action
Excessive vibration Build-up of foreign material on impellers Clean by flushing, or replace worn parts
Misalignment Level meter in piping
Worn bearings Replace bearings
Worn timing gears Replace timing gears
Impellers contacting body Rotate manually to verify impellers spin freely
High differential pressure Heavyweight or too much oil Check oil level and condition
Dirt deposits on impellers Remove dirt by flushing
Impellers out of time Retime impellers
Impellers contacting body Rotate manually to verify impellers spin freely
Low registration Upstream or bypass leak Check all valves for leakage
Non-registration Broken or binding index odometer Replace odometer
Obstruction in meter Remove meter, remove obstructions, flush meter
15. Troubleshooting
Figure 19. Horizontal installation
14. Auxiliary Equipment Mounting
All RABO meters are equipped with threaded holes for mounting
compact, lightweight auxiliary equipment [Figures 19 and 20].
All holes are M6 x 1 by 10mm deep. Heavier equipment should
be pipe or wall mounted adjacent to the meter. Elster provides
customized brackets for commonly used equipment [Figure 21].
Please contact your local Elster representative for details.
NPT AUXI LIAR Y POR TS
Figure 18. Auxiliary ports
Figure 20. Vertical installation
13. Thermowell
All RABO meters come equipped with two (2) ¼" NPT auxiliary
ports on the meter body [Figure 18], which can be used for sensing
pressure and temperature of the flowing gas. A thermowell is
required when using a temperature sensing device. Thermowells
are available as accessories to the meter.
a) Installing a Thermowell
1. If meter is not installed in the gas piping, go to Step 5.
2. Slowly open bypass valve.
3. Slowly close the meter’s outlet valve, then the inlet valve.
4. Slowly, completely depressurize the meter piping.
5. Remove one of the plugs in the meter body by using a
¼" hex key.
6. Apply Teflon tape or pipe dope to the male threads of the
thermowell. Wipe excess pipe dope off the thermowell
probe and leading threads to ensure no pipe dope
enters the metering chamber.
7. Screw the thermowell into the meter and tighten to
18 ft-lbs.
8. Re-pressurize the meter as instructed in Start-up/
Commissioning (see section 6).
Figure 21. Auxilary equipment mounted
ACC ESSO RY
16. Troubleshooting
ELSTER RABO® Rotary Gas Meter 15 Honeywell
Page 16
About Elster Gas
Elster provides best-in-class measurement and regulation products, systems and
solutions for the safe control and delivery of natural gas across the globe.
Trusted Brands
• Elster American Meter Company, LLC
• Elster Perfection Corporation
• Elster Instromet
• Elster Canadian Meter Company, LLC
• Elster Gas Depot
• Elster Meter Services
About Elster Gas
Elster provides best-in-class measurement and regulation products, systems and
solutions for the safe control and delivery of natural gas across the globe.
Trusted Brands
• Elster American Meter Company, LLC
• Elster Perfection Corporation
• Elster Instromet
• Elster Canadian Meter Company, LLC
• Elster Gas Depot
• Elster Meter Services
Elster American Meter Company, LLC
2221 Industrial Road
Nebraska City, NE 68410
USA
T +1 402 873 8200
F +1 402 873 7616
www.elster.com/gas
Elster is now part of Honeywell.
© 2017 by Elster. All rights reserved. Information contained
herein is subject to change without notice. Contact your Elster
representative for the most current product information.
Elster and Elster Logo are trademarks of Elster American Meter
Company LLC.
73023895a/03.2017/TKGG
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