Calculation Of Upstream And Downstream Distances - Honeywell ESSER 781443 Installation Instructions Manual

Venturi-Air Duct Kit

10.2 Calculation of upstream and downstream distances

Air duct with circular cross-section
d =
h
H
B
In order to exclude faulty measurements the air duct detector should be mounted in the same way as a flow
meter. For applications with a detector mounting close to reducing dampers and regulating flaps, filter units or
bends, the following minimum distances must be observed:
upstream
downstream
Fig. 3: Air duct detector after a bend in the duct system and downstream from an air intake (Example)
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2 x H x B
H + B
at least 3 x the nominal diameter of the air duct
at least 5 x the nominal diameter of the air duct
Air duct with rectangular cross-section
d = D
h
D
FB 798349 / 04.13