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Model 227A Dierential Pressure Indicator Section 2
Section 2—Installation
General
The instrument should be inspected at time of unpacking to detect any dam-
age that may have occurred during shipment.
IMPORTANT: The DPU was checked for accuracy at the factory. Do not change any of
the settings during examination or accuracy could be affected.
For applications requiring special cleaning/precautions, a polyethylene bag
is used to protect the instrument from contamination. This bag should be
removed only under conditions of extreme cleanliness.
Mounting/Piping/DPU Installation
Dimensional drawings are provided in Section 5, page 23. See Appendix A for
DPU installation and maintenance information.
Zero Check/Adjustment
Before placing the 227A indicator into service, check the zero indication, and
adjust if necessary. Zero adjustment can be accomplished without removing
the scale plate.
IMPORTANT: Adjusting the instrument's zero indication in accordance with the fol-
lowing procedure does not invalidate the original factory calibration or
warranty.
To check the zero indication, perform the following steps.
1. Mount the instrument in an approximately level position and connect to a
standard pressure source (see Appendix A).
2. If the zero indication is incorrect, adjust it as follows:
a. Remove the bezel and cover following the instructions provided in
Bezel/Lens (or Cover) Installation and Removal, page 9.
b. Using a 1/4" open-end wrench (included in calibration toolkit, Part
scale. See Figure 2.1, page 8.
c. Reassemble the unit, attaching the lens gasket, lens, and bezel to the
case per the instructions on page 9.
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