The Dwyer RMA-9-TMV is a Rate-Master Series RM polycarbonate variable area flowmeter that reads 15 to 150 SCFH air on a 2 in. (51 mm) direct-reading scale. It is fitted with a top mounted valve and has 1/8 in. female NPT connections.
Specifications verified October 12, 2026 against Dwyer DS-RM Rev. 3 (2/21), Bulletin F-43 (FR# 440197-00 Rev. 26, 8/23) and the Dwyer Series RM product page.
Best For
- Direct reading of 15 to 150 SCFH air with no conversion charts
- Air samplers and gas analyzers
- Pollution monitors
- Cabinet purging
- Medical equipment
- Panel mounted, surface mounted or piping-supported installations
Warranty
DwyerOmega limited warranty: free from defects in material and workmanship under normal use for one year from delivery, or such other period as specified in a product-specific warranty supplied with the product. Team Zot supports warranty claims at 855-825-2811 or sales@zotsupply.com.
Key Features
Direct-Reading SCFH Scale
The 2 in. (51 mm) scale reads 15 to 150 SCFH air directly, eliminating troublesome conversions.
Top Mounted Valve
Top mounted flow control valve. On vacuum air service the control valve belongs on the discharge side of the flowmeter, and the TMV unit may be applied there.
Stainless Steel Backbone
Absorbs piping torque to reduce installation damage and cost.
Shatter-Proof Polycarbonate Body
Durable body built for long operating life.
High Repeatability
Precision injection molding around a precision tapered pin, with integral flow guides that stabilize float movement.
Graduations on Both Sides
Scale graduations on both sides of the indicating tube give an instant flow reading.
ZOT Supply is an authorized distributor of Dwyer products.
Technical Specifications
| Series | Rate-Master Series RM, Model RMA |
| Flow Range | 15 to 150 SCFH |
| Calibrated Media | Air |
| Scale Length | 2 in. (51 mm) |
| Accuracy | 4% FS |
| Valve | Top mounted valve (TMV) |
| Process Connection | 1/8 in. female NPT |
| Pressure Limit | 100 psi (6.9 bar) |
| Temperature Limit | 130°F (54°C) |
| Service | Compatible gases and liquids |
| Wetted Materials | Body: polycarbonate; O-rings: neoprene and Buna-N; metal parts: stainless steel; float: stainless steel, black glass, aluminum, K monel or tungsten carbide depending on range |
| Calibration | Factory calibrated |
| Mounting Position | Vertical, inlet at bottom rear, outlet at top rear |
| Mounting Options | Through-panel (flush), surface mounted, or supported on piping |
| Panel Cutout (Flush Mounting) | 4-5/8 in. high x 7/8 in. wide (11.75 x 2.22 cm) |
| Surface Mounting Panel Holes | pipe 7/16 in. (1.11 cm), bolt 1/4 in. (0.64 cm) |
| Mounting Holes | 10-32 thread |
| Clamp Bolt Torque | 5 in-lb maximum |
| Dimensions (see drawing) | A 4-9/16 in. [115.90 mm]; F 1-3/16 in. [30.16 mm]; J (back width) 3/4 in. [19.05 mm]; K 4-13/16 in. [122.20 mm]; L 1 in. [25.40 mm] |
| Weight | 4 oz (113.4 g) |
| Compliance | Meets the technical requirements of EU Directive 2011/65/EU (RoHS II) |
Documentation
Frequently Asked Questions
What flow range does the Dwyer RMA-9-TMV measure?
The Dwyer RMA-9-TMV reads 15 to 150 SCFH air on a 2 in. (51 mm) direct-reading scale.
How accurate is the Dwyer RMA-9-TMV?
Accuracy is 4% of full scale (4% FS).
What are the pressure and temperature limits of the RMA-9-TMV?
The RMA-9-TMV is rated to 100 psi (6.9 bar) and 130°F (54°C). Do not exceed these limits.
How is the Dwyer RMA-9-TMV mounted?
Mount it vertically with the inlet at the bottom rear and the outlet at the top rear. It can be mounted through the panel using a 4-5/8 in. high x 7/8 in. wide (11.75 x 2.22 cm) cutout, surface mounted, or supported on rigid piping. Do not exceed 5 in-lb on the clamp bolts.
Can the Dwyer RMA-9-TMV be used on vacuum air service?
Yes. On vacuum air service the flow control valve should be on the discharge side of the flowmeter, and the top mounted valve unit may be applied for this. Keep inlet piping as short and open as possible so the meter operates near atmospheric pressure.
Do SCFH readings on the RMA-9-TMV need correction for pressure and temperature?
Yes, when operating conditions differ from standard. The SCFH scale is calibrated to standard conditions of 14.7 psia and 70°F. Correct the observed reading with Q2 = Q1 x square root of ((P1 x T2) / (P2 x T1)), using absolute pressure and temperature measured at the flowmeter inlet when the top mounted valve is used under vacuum, otherwise at the exit.
What size are the process connections on the RMA-9-TMV?
The RMA-9-TMV has 1/8 in. female NPT connections. Inlet and discharge piping should be at least as large as the connection (1/8 in. IPS).
What fluids should not be used with the RMA-9-TMV?
Caustic solutions, antifreeze (ethylene glycol) and aromatic solvents should not be used, and solutions of acids, bases or salts with a pH below 5.0 or above 8.5 should be avoided. Keep the installation away from strong chlorine atmospheres and solvents such as benzene, acetone and carbon tetrachloride.
Can the RMA-9-TMV be cleaned without removing the piping?
Yes. First make sure the flowmeter is unpressurized and drained of any liquid. Remove the four mounting bracket screws and pull the body forward; the piping connections stay intact. Remove the top mounted valve by pulling up gently on the valve knob to release the valve body seals. Clean the flow tube and body with pure soap and water and a soft brush.
