Malfunctions 
 
HON 380 gas pressure regulator with HON 673/674 controller    38 
 
Malfunction  Possible causes  Correction 
Unstable outlet pres-
sure behavior (oscilla-
tions) 
The regulator is not being op-
erated with sufficient differen-
tial pressure 
Increase the differential pres-
sure with the regulator 
The regulator unit’s diaphragm 
is too soft 
Check the regulator unit’s dia-
phragm; contact the manufac-
turer if necessary 
The throttle valve setting is not 
correct 
Adjusting the throttle valve on 
the measuring line of the regu-
lator unit (see page 36)