Gauge heads should be mounted as close as possible to the point at which the
pressure is to be measured. Use a short branch tube with an internal diameter
no less than that of the gauge head. Long, narrow and angled connections can
cause a significant reading error.
The Penning gauge head will operate at any attitude but mounting vertically
(with the flange horizontal and facing downwards) is recommended so as to
avoid the possibility of debris falling into the gauge head.