Bulletin C-11
AIR FLOW
13/16
[20.64]
1-5/16
[33.34]
E
2
[50.80]
4
[101.60]
Series 250-AF Inclined Manometer Air Filter Gages
Installation and Operating Instructions
Note: The drawing above shows standard connection at left and three-way
vent valve at right. If the optional vent valves are preferred, please note
that two are required.
Range Inches of
Model
250 - AF
250.5 - AF
251 - AF
252 - AF
350 - AF
209 - AF
260 - AF
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: 219/872-9057 e-mail: info@dwyer-inst.com
Water (Pa)
.10 - 0 - 1.0
(24.82 - 248.9)
.10 - 0 - 1.0
(24.82 - 248.9)
.05 - 0 - .50
(12.41 - 124.1)
.20 - 0 - 2.0
(49.64 - 487.8)
0 - 4
(0 - 995.6)
.20 - 0 - 3.0
(49.64 - 746.7)
0 - 1.5
(0 - 372.9)
Scale
Divisions
Inches (cm)
.02
(.05)
.01
(.025)
.01
(.025)
.02
(.05)
.10
(.254)
.02
(.05)
.02
(.05)
Scale
Length
Inches (cm)
5-1/2
(13.97)
8
(20.32)
5-1/2
(13.97)
8
(20.32)
4-1/2
(11.43)
8
(20.32)
5-1/2
(13.97)
Dimensions – Inches (Centimeters)
A
2-13/16
(7.14)
3-1/8
(7.94)
2-15/16
(7.46)
2-13/16
(7.14)
Vertical Manometer – Dimensions Not Shown
2-3/4
(6.99)
2-13/16
(7.14)
B
8-1/2
(21.59)
11-3/6
(28.89)
8-1/4
(20.96)
11-1/6
(28.26)
11-1/4
(28.58)
8-3/8
(21.27)
C
4-1/8
(10.48)
3-15/16
(10.00)
3-5/16
(8.41)
5-1/2
(13.97)
7
(17.78)
4-15/16
(12.54)
D
1-1/2
(3.81)
1-1/2
(3.81)
1-1/2
(3.81)
2
(5.08)
2
(5.08)
2
(5.08)
E
7-3/4
(19.69)
10-5/8
(26.99)
7-1/2
(19.05)
10-3/8
(26.35)
10-1/2
(26.67)
7-5/6
(19.37)
Phone: 219/879-8000 www.dwyer-inst.com
Bulletin C-11
Page 2
INSTALLATION
1. Select a convenient location and drill two 1/2˝ (12.7 mm) holes “E”
inches/centimeters apart on a horizontal line. Mount the gage with the
toggle bolt assemblies, adjust to a level position as indicated by the
spirit level, and tighten securely.
2. Drill two 7/16˝ (11.1 mm) holes in the duct, one on each side of the
filter and at least 12˝ (30.48 cm) distant. Secure the static pressure tips
as in the drawing above, with the tips directed into the air flow.
3. Connect 1/4˝ (6.35 mm) metal tubing from static pressure tips to the
gage. The tip on the downstream or fan side of the filter leads to the
right-hand gage connection, etc.
4. Slip out both gage connector plugs, venting both sides of the gage to
atmosphere, and slide scale so that the zero mark lies directly behind
the fluid meniscus, as in the drawing. Align fluid meniscus and the
reflected image to eliminate parallax error.
5. Add or remove fluid as necessary.
6. Replace both gage connector plugs, and the gage will indicate the
pressure drop across the filter.
7. Filter manufacturers provide figures covering the pressure drop
through their filters, at rated volume, when new and after use. Thus, for
a typical filter, initial resistance might be .25˝ of water (62.05 Pa) and
permissible increase .30˝ water (74.46 Pa). Such a filter should be
serviced at a gage reading of .55˝ water (136.5 Pa).
CAUTION:
Use Dwyer Instruments, Inc. gage fluid only. Clean with soap and water
only. Other fluids or cleaning agents may damage the gage.
©Copyright 2012 Dwyer Instruments, Inc. Printed in U.S.A. 10/12 FR# 32-440239-00 Rev. 6
DWYER INSTRUMENTS, INC.
Phone: 219/879-8000 www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: 219/872-9057 e-mail: info@dwyer-inst.com