Dwyer RMV User Manual

Series RMV Rate-Master®Flowmeters

Specifications — Installation and Operating Instructions

Bulletin F-52

Series RMV Rate-Master

dependable measurement of water flows to 20 GPM. Installed in-line,
they employ a “target” type element linked to a flexible leaf spring which
deflects in proportion to the force generated by the flowing medium.
A magnet attached to the free end of the spring drives a mating magnet
to which the indicating pointer is attached. Because the spring/magnet
assembly is isolated from the mating magnet/pointer assembly by a wall
in the brass casting, there is no direct mechanical linkage. This means
units can easily withstand over-range flows to 150% without damage
and there is no path for leaks. This construction also allows units to be
specially calibrated for dark and/or opaque liquids which would be
impossible to see with typical rotameter style instruments. Models are
available with 1/2˝, 3/4˝ or 1˝ female connections.

CALIBRATION

All Series RMV flowmeters are calibrated at the factory for mounting with
scale vertical and flow from left to right when facing unit. They must be
used in that position for accurate readings. If flowmeter was specially
calibrated for some other position, it will be marked accordingly.

These flowmeters will normally retain their original accuracy for the life
of the device. If, at any time you want to check calibration, do so only
with instruments of certified accuracy. Do not attempt to check the RMV
Rate-Master®flowmeters with other flowmeters piped in a series. Even
minor variations in piping and back pressure can cause a significant
difference in indication. Your flowmeter may be returned to the factory
for a calibration check at no charge. This no-charge check does not
include written certification or any repairs necessary to restore proper
operation.

®

Dial-Type Flowmeters provide accurate,

SPECIFICATIONS
Service: Compatible liquids.
Wetted Materials: Brass, copper, 302 SS, sintered barium ferrite.
Temperature Limits: 20 to 200°F (-6.7 to 93°C).
Pressure Limit: 1000 psig (68.9 bar).
Pressure Drop: 0-5 GPM: 3.2 PSID; 0-10 GPM: 5.3 PSID; 0-20 GPM:

10.4 PSID.

Accuracy: ±2% of full scale.
Size: Diameter dial face 4˝ (101.6 mm).
Process Connections: See Chart.
Maximum Flow: 1.5 x full scale reading.
Weight: 9 Ib (4.08 kg).

Model
RMV-1-3
RMV-2-3
RMV-3-3
RMV-1-2
RMV-2-2
RMV-3-2
RMV-1-1
RMV-2-1
RMV-3-1

Range, GPM Water

0-5
0-10
0-20
0-5
0-10
0-20
0-5
0-10
0-20

Connection Size

1˝ female NPT
1˝ female NPT
1˝ female NPT
3/4˝ female NPT
3/4˝ female NPT
3/4˝ female NPT
1/2˝ female NPT
1/2˝ female NPT
1/2˝ female NPT

DWYER INSTRUMENTS, INC.

Phone: [phone] www.dwyer-inst.com

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]

LOCATION

Y

Select a location where the flowmeter can be easily read and where the
temperature will not exceed 200°F (93°C).

The mounting surface and piping to the flowmeter should be free from
excessive vibration. If pulsing flow or vibration causes excessive pointer
oscillation, contact factory for ways to provide additional dampening.

PIPING
Inlet Piping: It is good practice to approach the flowmeter inlet with as

few elbows, restrictions, and size changes as possible. Inlet pipe should
be as close to the flowmeter connection size as practical to avoid
turbulence which can occur with drastic size changes. The length of inlet
piping has little effect on normal pressure-fed flowmeters.

Discharge Piping: Piping on the discharge side should be at least as
large as the flowmeter connection.

Zero Setting: The RMV Rate-Master®flowmeter is calibrated and
zeroed in a specific (normally vertical) position at the factory. If the gage
is used in any other position, it may be necessary to adjust the zero
setting. Position changes can aversely affect accuracy.

If re-zeroing is required, hold the brass case firmly with one hand and
turn the grey bezel cover counterclockwise to remove. Next, lift off the
plastic cover. Hold the 5/32˝ diameter brass knob below the pointer axis
stationery and adjust the rectangular brass blade between axis and
knob. Repeat adjustments as necessary until flowmeter reads exactly
zero when held in its intended mounting position.

To replace the cover, align the (2) 1/8˝ slots on the edge with matching
1/8˝ projections on the case adjacent to the pointer bumpers. Install the
bezel ring, hold cover in place with palm of hand and turn ring clockwise
until tight.

MOUNTING
In-Line Mounting: Flowmeter may be installed in-line supported only by

the piping. A square wrench surface surrounds the outlet port to aid in
assembly.

Surface Mounting: Drill (4) 3/16˝ diameter holes in the panel using
dimensions shown in the drawing below.

Attach with 6-32 machine screws of appropriate length. For many metal

panels the 5/16˝ screws included can be used.

Flush Mounting: If required, re-zero flowmeter before panel mounting.
Provide a 4-3/4˝ (120 mm) opening in panel. Place flowmeter into
opening and attach (4) mounting lugs to rear of case with 6-32 X 5/16˝
machine screws. Secure unit in place by tightening (4) 6-32 X 3-1/2˝
screws through the mounting lugs against the rear of the panel.

OPERATION

POINTER POINTER AXIS

BRASS BLADE
ADJUST AS NECESSARY

BRASS KNOB
HOLD STATIONAR

If flowing media is dirty, install a 50-micron filter upstream from the
flowmeter inlet. After all connections are complete, introduce flow as
slowly as possible to avoid damage. With liquid flows, it may be
necessary to purge air from the system before pointer readings stabilize.

MAINTENANCE

The moving parts of these flowmeters need no routine maintenance or
lubrication. The only adjustment is the zero setting which should be
checked periodically. Units in need of repair should be returned to the
factory prepaid. Field repair is not recommended.

©Copyright 2011 Dwyer Instruments, Inc. Printed in U.S.A. 2/11 FR# 50-440721-00 Rev. 4

DWYER INSTRUMENTS, INC.

Phone: [phone] www.dwyer-inst.com

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]