The Dwyer VFCII-122 is a Visi-Float VFCII Series acrylic variable area flowmeter with a 5 in. direct-reading scale for 5 to 50 SCFM of air. It has 1 in. male NPT back connections with acetal thermoplastic fittings and an accuracy of 2% of full scale.
Specifications per Dwyer DS-VFC-VFCII EN Datasheet v1 (0826) and Dwyer Bulletin F-48 Rev. 5 (6/20), reviewed 2026-10-18.
The VFCII-122 measures air flow from 5 to 50 SCFM on a scale hot stamped into a body cut and precision machined from solid, clear acrylic. A stainless steel float rides in a precision machined tapered bore against a white background, and the wetted parts are acrylic, Buna-N O-rings, stainless steel metal parts and acetal thermoplastic fittings. It is rated 100 psig (6.9 bar) at 120 °F (48 °C) and mounts vertically with the inlet at the bottom. The SCFM scale is referenced to standard conditions of 14.7 psia and 70 °F, and gas readings taken at other pressures or temperatures are corrected back to standard conditions.
Best For
- Direct reading of 5 to 50 SCFM air
- Air samplers and gas analyzers
- Pollution monitors
- Cabinet purging
- Medical and laboratory equipment
- Remediation
- Panel mounting with the process piping connected behind the panel
Warranty
Covered by the Dwyer factory warranty. Damage due to contact with incompatible gases or liquids is not covered by warranty. Contact ZOT Supply at sales@zotsupply.com or 855-825-2811 for warranty terms.
Key Features
Direct-Reading SCFM Scale
The 5 in. scale reads 5 to 50 SCFM air directly. Scales are hot stamped into the plastic, eliminating troublesome conversions and increasing operating life. Readings at nonstandard gas pressure or temperature are corrected to standard conditions.
Solid Acrylic Body
Cut and precision machined from a solid, clear acrylic block, allowing complete visual inspection.
Precision Tapered Bore
A precision machined tapered bore enables high repeatability.
White Background
A white background improves float visibility, increasing reading accuracy.
Back Connections
1 in. male NPT back connections with acetal thermoplastic fittings. Surface mounts on a panel with #10-32 machine screws, or installs in-line supported only by the piping.
Factory Calibrated
Calibrated at the factory, and normally remains within its 2% of full scale accuracy tolerance for the life of the device. Calibration services are available, including a NIST traceable calibration certificate (-NIST option).
ZOT Supply is an authorized distributor of Dwyer products.
Technical Specifications
| Series | Visi-Float VFCII Series |
| Model Code | VFCII-122 |
| Flow Range | 5 to 50 SCFM |
| Scale Media | Air |
| Scale Length | 5 in. typical length |
| Accuracy | 2% of FS |
| Service | Compatible gases and liquids |
| Process Connection | 1 in. male NPT back connections |
| Wetted Materials | Body: acrylic plastic; O-ring: Buna-N (fluoroelastomer available); Metal parts: SS; Float: SS; Fittings: acetal thermoplastic |
| Temperature and Pressure Limits | 100 psig (6.9 bar) @ 120 °F (48 °C) |
| Mounting Position | Vertical, inlet connection at the bottom and outlet at the top |
| Mounting | Surface mount with #10-32 machine screws, or in-line supported only by the piping |
| Fitting Torque | 10 ft-lb (13.56 N-m) maximum; hand tighten only |
| Calibration | Factory calibrated |
| Body Dimensions | 10-1/2 in. (266.70 mm) long x 1-3/4 in. (44.45 mm) wide x 2 in. (50.80 mm) nominal depth |
| Mounting Hole Layout | Three holes for #10-32 machine screws: one 3 in. (76.20 mm) from the bottom of the body, and a pair 1-1/8 in. (28.58 mm) apart located 4-1/2 in. (114.30 mm) above it |
| Overall Length | 11 in. (279.40 mm) with back connections |
| Back Connection Spacing | 8-1/2 in. (215.90 mm) center to center |
| Weight | 24 to 25 oz (0.68 to 0.71 kg) |
| Compliance | Meets the technical requirements of EU Directive 2011/65/EU (RoHS II) |
| Options (Order Suffix) | -BSPT: BSPT process connections; -FDA: 316 SS float and guide rod (available only with fluoroelastomer O-rings); -NIST: NIST traceable calibration certificate; -VIT: Fluoroelastomer O-rings |
Documentation
Frequently Asked Questions
What flow range does the Dwyer VFCII-122 measure?
The VFCII-122 reads 5 to 50 SCFM of air directly on a 5 in. scale, with an accuracy of 2% of full scale.
What process connections does the VFCII-122 have?
The VFCII-122 has 1 in. male NPT back connections with acetal thermoplastic fittings.
What are the pressure and temperature limits of the VFCII-122?
The VFCII-122 is rated 100 psig (6.9 bar) @ 120 °F (48 °C).
How do I mount the VFCII-122?
Mount the VFCII-122 vertically with the inlet connection at the bottom and the outlet at the top, on a surface and piping free from vibration. For surface mounting, drill three holes for #10-32 machine screws plus two clearance holes for the back connection fittings, and install the screws from the rear; screws must not be longer than the panel thickness plus 3/8 in. The meter can also be installed in-line supported only by the piping.
Where should the VFCII-122 be installed?
Choose a location where the meter can be easily read, the temperature will not exceed 120 °F, and the mounting surface and piping are free from vibration. Arrange the piping so it places no stress on the fittings or the flowmeter body. Avoid strong chlorine atmospheres and solvents such as benzene, acetone and carbon tetrachloride; damage from incompatible gases or liquids is not covered by warranty.
How should the VFCII-122 be piped?
Approach the inlet with as few elbows, restrictions and size changes as possible, with inlet piping as close to the 1 in. connection size as practical, and make the discharge piping at least as large as the flowmeter connection. On air or gas service, keep the discharge piping as short and open as possible. For vacuum service, keep the inlet piping short and open and install any flow control valve on the discharge side of the flowmeter.
How do I read the VFCII-122?
Introduce flow as slowly as possible to avoid damage. Once the float has stabilized, locate the highest point of greatest diameter on the float and align it with the theoretical center of the scale graduation; between graduations, estimate the float position between the two closest graduations.
How do I correct a VFCII-122 reading for pressure and temperature?
The SCFM scale is referenced to standard conditions of 14.7 psia and 70 °F (530 R). Corrected flow Q2 = Q1 x √((P1 x T2) / (P2 x T1)), where Q1 is the observed reading, P1 is the actual pressure (14.7 psia + gage pressure), P2 is 14.7 psia, T1 is the actual temperature (460 + °F) and T2 is 530 R. Measure pressure and temperature at the flowmeter outlet, or at the inlet under vacuum.
How do I check the calibration of the VFCII-122?
It is calibrated at the factory and normally remains within its accuracy tolerance for the life of the device. Re-check it only with instruments or equipment of certified accuracy, not against a similar flowmeter, since minor variations in piping and back pressure can cause significant differences. The flowmeter can also be returned to the factory and checked for conformance at no charge.
What options are available for the VFCII-122?
The VFCII-122 is the standard model with NPT connections and Buna-N O-rings. Dwyer offers these options as order suffixes: -BSPT, BSPT process connections; -FDA, 316 SS float and guide rod (available only with fluoroelastomer O-rings); -NIST, NIST traceable calibration certificate; -VIT, fluoroelastomer O-rings.
How tight should the fittings on the VFCII-122 be?
Hand tighten only. Do not overtighten fittings or piping into fittings; the maximum recommended torque is 10 ft-lb (13.56 N-m).
What is the difference between the VFCII-122 and the VFC-122?
Both read 5 to 50 SCFM air with the same 5 in. scale, accuracy and ratings. The VFCII-122 has 1 in. male NPT back connections with acetal thermoplastic fittings; the VFC-122 has 1 in. female NPT back connections with PVC fittings.
How is the VFCII-122 cleaned?
Wash the body and parts in a mild soap and water solution; a soft bristle bottle brush simplifies cleaning the flow tube. Avoid benzene, acetone, carbon tetrachloride, gasoline, alkaline detergents, caustic soda and liquid soaps, and avoid prolonged immersion.
- Series:
- VFCII
- Product Type:
- Variable Area Flowmeter
- Media:
- Air
- Flow Range:
- 5-50 SCFM
- Connection Type:
- Male NPT
- Connection Size:
- 1 in.
- Body Material:
- Acrylic
- Max Pressure:
- 100 psi
- Accuracy:
- 2% FS
- Mounting:
- Vertical
- NIST Calibration:
- Available
