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1211 Handy Roll-Up Manometer with Laboratory Accuracy 
Dwyer Slack-Tube® Manometers are as accurate as the finest laboratory "U" gages - yet they are made to roll up compactly for easy carrying and to withstand rough usage. 

Simply unroll the Dwyer Slack-Tube® Manometer and set up to read static pressure, vacuum, or differential pressure. Magnetic clips hold it firmly to any steel surface or hang it on a nail. Turn connectors one revolution to open. When the pressure is imposed, add the number of inches one column travels up to the number of inches the other column travels down. When reading is completed turn connectors to seal columns, roll up manometer into compact coil and tuck it away in its circular metal case or a tool box. No fluid lost. No loose caps or inserts to lose. 

Dwyer Slack-Tube® Manometers cover a wide range of pressure readings - from 4-0-4 inches up to 60-0-60 inches. Use them in determining velocity and static pressures, for leakage, fan and blower tests, calibrating control devices, checking gas pressure and many other applications. All models have flexible vinyl-plastic columns and flexible spring steel scale calibrated in inches of water using water; and inches of mercury using mercury. Scale is center-mounted between columns to eliminate parallax error and has a full 2" sliding zero adjustment. 

All Dwyer Slack-Tube® Manometers feature exclusive molded nylon tubing connector assemblies with rapid shutoff design in an acrylic plastic top. One turn counter clockwise and the instrument is ready for use. Another turn seals the tubes completely. Molded all-nylon construction makes this assembly corrosion-proof, leakproof and practically unbreakable. Tubing connectors extend horizontally allowing 360° freedom. Tubes won't bend or pinch off. 

All models have over pressure safety traps in the top of both columns to prevent loss of fluid due to over range pressures or surges in pressure. 

Slack-Tube® Manometers are suitable for intermittent total pressure to 50 psi and vacuum not exceeding 20" Hg. Avoid temperatures above 130°F and continuous high total pressure. Not for use with red gage oil; use only water or mercury. 

1212 Gas Pressure Kit For Servicing Gas Appliances 

A handy, complete kit containing a 16" Slack-Tube® Manometer, necessary tubing and connection fittings for checking gas pressures in virtually all gas appliances such as water heaters, furnaces, stoves and dryers. Different range manometers may be specified at corresponding prices. Compared to the cost of purchasing items separately the assembly of component parts into kit form represents substantial savings. 

What the kit consists of: 

   1 - #1211-16 Slack-Tube® Manometer, reads pressure to 16" water*.
   1 - Carrying case, plastic, 8-1/2" x 7" x 3-1/8".
   1 - 3/4 oz. Bottle Fluorescein green color concentrate with wetting agent.
   1 - 1/8" pipe thread rubber tubing adapters.
   1 - 1/8" to 1/4" pipe thread bushing.
   1 - 3 ft length 3/16" rubber tubing.
   1 - Rubber tubing adapter to fit standard 7/16" diameter spud. 

*Other ranges available

1211 Slack - Tube Manometer extended
1211 Slack- Tube Manometer
1212 Gas Pressure Kit

Range, In

Slack-Tube Manometers
These inexpensive manometers measure positive, negative and differential pressures. Dwyer Flex-Tube® U-Tube Manometers combine the inherent accuracy of the simple "U" Tube with the durability of tough, long-lasting plastic construction. Columns are of .375" O.D. flexible and shatter proof clear butyrate tubing. They are easily accessible for cleaning. Indicating tube is backed by white scale channel to provide maximum color contrast. Scales are extruded high impact polystyrene plastic, formed to hold columns in perfect alignment. Stark white scales have graduations and numbers silkscreen-printed in black for maximum legibility. 

You can choose from numerous models and features including over-pressure safety traps, in full scale ranges from 8" to 36" of water or mercury. All are suitable for total pressures to 100 psi - for determining velocity and static pressures, leakage, fan and blower efficiency, filter resistance, and gas pressures. Ideal wherever a portable, direct reading manometer is needed. Standard ranges and markings as shown, or special ranges, colors, logos and brand names for OEM quantity orders are available.
Flex-Tube U-Tube Manometers
The Dwyer Series 475 Mark III Handheld Digital Manometer is ideal for field calibration, monitoring or trouble shooting HVAC systems, clean rooms or a wide range of other low pressure pneumatic systems. This handy instrument measures positive, negative or differential pressures of air and natural gases in ranges from 1 in. w.c. (0.249 kPa) to 150 psid (10.34 bar). The Series 475-FM is approved and is intrinsically safe for hazardous locations, Class 1, Div.1, Group A, B,C, D, T4. Its simple operation and easy to read digital display make it an indispensable test instrument for the plant engineer, industrial hygienist and HVAC technician. When used with a Dwyer Pitot tube (see Air Velocity), the Series 475 Mark III can also be used as an air velocity gage. See the complete 475-1-FM-AV kit on the "Options/Accessories" page. 

The Series 475-FM Mark III is housed in a durable extruded aluminum case with its solid state circuitry mounted on a tough fiberglass epoxy circuit board. A standard 9 volt battery provides up to 100 hours of operation. Dual push pads on the front panel control on-off operation and English or metric pressure unit selection. No setup or leveling. Zero adjust knob is conveniently located on top. The large 1/2" LCD display is easy to read, minimizing data collection errors. Units include a "low battery" indicator. The pressure sensor used is a highly stable silicon piezoresistive device. Standard connections are dual sized for 1/8" or 3/16" I.D. vinyl or rubber tubing. Complete instructions are conveniently printed on rear of housing.

Mk III Handheld Digital Manometer
Ranges from 1 in w.c. to 150 psid, ±0.5% Accuracy 
Series 475 - FM Mark III$273.75