Honeywell HON 380 User And Maintenance Instructions page 25

Downstream of the
sensing point
Details
HON 380 gas pressure regulator with HON 673/674 controller
Depending on the specific system design, the L
pipes downstream of the sensing point must be (1.5 to 4) x DN of the pipe:
Undisturbed length of pipe
L min. 1.5 x DN
uR
L min. 1.5 x DN
uR
L min. 3 x DN
uR
L min. 4 x DN
uR
 Shut-off devices with an undisturbed flow pattern (such as full bore ball
valves) and, if applicable, pipe bends (depending on the design) are consid-
ered to be non-disturbing elements in terms of measuring line connections.
 For gas meters (turbine gas meters including quantometers, ultrasonic gas
meters, and vortex flow meters, but NOT rotary piston gas meters), there are
no restrictions in terms of measuring line configurations, as these meters are
not considered to be flow-disturbing within this context.
 The following applies to rotary piston gas meters: Minimum distance be-
tween gas pressure regulator or reducer / expander and gas meter:
L min. 3 x DN.
uR
 Measuring line connections downstream of gas meters must be at a dis-
tance of L min. 2 x DN.
uR
 If shut-off valves are used (reduced bore), the recommended distance down-
stream of a measuring line is L
 Gas meter pressure losses must be taken into account based on system con-
ditions if applicable.
Basics for installing the device in a pipe
lengths of the undisturbed
uR
for
Thermowells
Reducers and expanders, depending on the
specific system conditions
Shut-off devices (gate valves, check valves,
and reduced bore ball valves)
Tees
min. 3 x DN.
uR
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