Series 250-AF Inclined Manometer Air Filter Gages

Precision Machined, Solid Acrylic Plastic Gages, Accurate To ±1% Of Full Scale

Dwyer® Durablock® SERIES 250-AF Gages are precision machined 1" thick solid acrylic plastic, virtually unbreakable and free of distortion. The fluid bore is precision drilled to ±.0002" to assure life long accuracy. A glass spirit level is built into the body and encapsulated to prevent damage or tampering. The scale is mirror polished chrome plated brass to assure parallax free reading by alignment of the meniscus with its reflection. Safety traps are incorporated in the body to prevent loss of fluid due to pressure surges. Red and green signal flags indicate clearly when a filter change is necessary. Gages are suitable for use in ambient temperatures of -20 to 150°F. Connection fittings are positively sealed by "O" rings but easily removed for zeroing or addition of fluid. Furnished complete with instructions.

Economy Model 452-AF is similar to 250 Series except that it is not equipped with over pressure traps. Two A-324 1/4" compression fittings are included with each gage but not shown. Bodies are of 5/8" thick acrylic and scales are mirror polished, epoxy coated aluminum.

Click here, if you require a Safety Data Sheet for the Red Gage Fluid.

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Product Applications

  • Air filter gage

Models & Ordering

Model Description Usually Ships Price Order
209-AF
Ships: Same Day
Price: $383.00
Inclined air filter gage, range .20-0-3.0" w.c., 5-1/2" inclined scale, Same Day $383.00 Order
250.5-AF
Ships: Same Day
Price: $336.00
Inclined air filter gage, range .10-0-1.0" w.c., 8" inclined scale, Same Day $336.00 Order
250-AF
Ships: Same Day
Price: $318.00
Inclined air filter gage, range .10-0-1.0" w.c., 5-1/2" inclined scale, Same Day $318.00 Order
251-AF
Ships: 1-2 Weeks
Price: $346.00
Inclined air filter gage, range .05-0-.50" w.c., 5-1/2" inclined scale, 1-2 Weeks $346.00 Order
252-AF
Ships: Same Day
Price: $354.00
Inclined air filter gage, range .20-0-2.0" w.c., 8" inclined scale, Same Day $354.00 Order
260-AF
Ships: 1-2 Weeks
Price: $346.00
Inclined air filter gage, range 0-1.5" w.c., 5-1/2" inclined scale, 1-2 Weeks $346.00 Order
350-AF
Ships: 1-2 Weeks
Price: $363.00
Inclined air filter gage, range 0-4" w.c., 4-1/2" inclined scale 1-2 Weeks $363.00 Order
451-AF
Ships: 1-2 Weeks
Price: $318.00
Inclined air filter gage, range 0-1" w.c., 8" inclined scale 1-2 Weeks $318.00 Order
452-AF
Ships: 1-2 Weeks
Price: $326.00
Inclined air filter gage, range 0-2" w.c., 8" inclined scale, 2 psi max. pressure. 1-2 Weeks $326.00 Order

Specifications

For Architects and Engineers
An air filter gage for measuring the resistance to air flow through the filters shall be installed, one for each bank of filters. The gage shall be of inclined tube differential type (equipped with vent valves for zeroing) shall be of solid acrylic plastic construction with built-in level vial (and over pressure safety traps 250 Series only), shall have an adjustable mirror-polished scale, shall be furnished complete with two 5-foot lengths 1/4" tubing, two static pressure tips, mounting hardware, additional bottle of red gage fluid and instructions.

Features

  • High accuracy and easy to use, making it a dependable device for many years of service
  • Easy to read polished inclined scale allows minute pressure differences to be read
  • No moving parts mean no calibration or nothing to wear out

Accessories

Model Number Description Usually Ships Price Order
3-way vent valve, plastic, 1/8 A-310B 3-way vent valve, plastic, 1/8" NPT to 1/4" metal tubing, 10 psi rating. Same Day $11.50 Order
Gage connector, 1/8 A-317 Gage connector, 1/8" pipe thread opening, less OD thd., for slip fit in 3/4" dia opening in 250 Series AF gages. Same Day $17.75 Order
1 oz dispenser bottle of red gage fluid, .826 sp. gr. A-101 1 oz dispenser bottle of red gage fluid, .826 sp. gr. Same Day $7.30 Order
4 oz bottle of red gage fluid, .826 sp. gr. A-102 4 oz bottle of red gage fluid, .826 sp. gr. Same Day $14.00 Order
1 pt bottle of red gage fluid, .826 sp. gr. A-103 1 pt bottle of red gage fluid, .826 sp. gr. Same Day $32.25 Order
1 qt bottle of red gage fluid, .826 sp. gr. A-104 1 qt bottle of red gage fluid, .826 sp. gr. Same Day $60.50 Order
Gage connector for 1/4 A-322 Gage connector for 1/4" tubing, slip fits in 3/4" opening in 250 Series AF gages (compression nut and ferrule not included). Same Day $7.50 Order
Compression fitting, brass 1/8 A-324 Compression fitting, brass 1/8" NPT to 1/4" metal tubing. Same Day $4.00 Order
420103-00 Red scale arrow. 1-2 Weeks $1.70 Order
420104-00 Green scale arrow. 1-2 Weeks $1.70 Order
Aluminum tubing is recommended for permanent installations. 1/4 A-210 Aluminum tubing is recommended for permanent installations. 1/4" OD, 5' length, 500 psi maximum pressure @ 200°F. Same Day $5.99 Order
A-603 "T" kit, accessory package for using pressure switch in conjunction with an air filter kit equipped Magnehelic® or Series 250 AF gages, includes two 1/8" NPT to 1/4" tubing compression fittings & two compression tees. Same Day $18.25 Order

Drawings

Questions

Question
Is routine maintenance required for a Dwyer red gage fluid type manometer?
Answer
Yes. The zero point should be checked periodically as well as the fluid level. After a year of service, particularly with dirty air, the fluid should be replaced to assure that specific gravity changes are not affecting the accuracy of the reading.
Question
We are using a Durablock inclined manometer with a range of 0-0.25" of water. What is considered a normal response time to steady state? We are seeing times of 1 minute whereas the manual states 'a few seconds'. Gage fluid is well beyond the recommended three years. Do I need fresh (i.e. new) gage fluid? My supply is as old as what's in the manometer.
Answer
The manometers have a response time that is dependent on the length of tubing, so a response time of a minute is not uncommon. You may want to check your fittings to make sure there is not a clog present. The gage fluid has a lifespan of three years before the inherent properties start to change, so it is suggested to replace it. A one ounce bottle of fluid is p/n A-101.
Question
What is the advantage of using a manometer rather than a Magnehelic® gage?
Answer
Dwyer Instruments manufactures many different types and styles of manometers with various accuracies and prices for different applications as well as the Magnehelic® gage. For example, some of the many manometers we manufacture are Hook Gage Manometers with ±0.001 inches water column accuracy; Microtector® Portable Electronic Point Gage to ±0.00025 inches water column accuracy; Handheld Digital Manometers with ±0.5 inches water column accuracy; very inexpensive Mark II Molded Plastic Air Filter Gages at ±3% inches water column accuracy. The key point is that we offer many manometers and the selection depends on your specification, application, convenience needs and pocketbook. Some of the key factors to consider that affect manometer performance and usage are: Characteristics of Indicating Fluid, Readability and Leveling. You should read "Measurement of Pressure with the Manometer" in our catalog to fully understand the importance of these factors and their effect on your reading with the manometer instrument. For many applications people prefer to use our Magnehelic® (dial style) gage with ±2% inches of water column accuracy because of convenience, accuracy, etc., plus when compared to a manometer, it eliminates indicating fluid, need for leveling, and some prefer the readability. If you consider manometers and Magnehelic® gages to measure low air or gas pressures ­ positive, negative, or differential, you have a wide selection to choose from and your application needs can be met with our very broad product line at a great value.

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