Dwyer 422 - Manual

1. Mount gage securely on a vertical surface avoiding excessive heat.
(Temperatures over 150°F (65.6°C) will damage gage). Level gage
approximately by swinging gage about top center mounting screw and locate
bottom bracket screws in center of slots.
2. Turn pressure connectors counter clockwise 1/4 to 1/2 turn, thus venting
gage to atmosphere.
3. Center bubble between guide lines on spirit level by swinging about top
center mounting screw and tighten bottom bracket screws.
4. Turn fluid level adjustment knob to set the meniscus of the fluid column at
zero, as in photo.
Align fluid meniscus and the reflected image to eliminate parallax error.
5. Add or remove fluid as necessary.
6. Use left hand pressure gage connection for positive (+) (above atmospheric)
pressures. Connect to right side pressure connection for negative (-) (below
atmospheric) pressures. Connect to both pressure connections for
differential pressures, as with a Pitot tube.
CAUTION:
Use Dwyer gage fluid only. (See Gage Scale for Proper Specific Gravity). Clean
with mild soap and water only. Other fluids or cleaning agents may damage the
gage.
AIR VELOCITY
The total pressure of an air stream flowing in a duct is the sum of the static or
bursting pressure exerted upon the sidewalls of the duct and the impact or velocity
pressure of the moving air. Through the use of a Pitot tube connected differentially
to a manometer, the velocity pressure alone is indicated and the corresponding air
velocity determined.
Series 421-422 Stationary Gage
Operating Instructions
Bulletin D-5
DWYER INSTRUMENTS INC.
MICHIGAN CITY, IN 46360 U.S.A.