Badger Meter Cox Precision Turbine Meters - Manual (Page 10)

TROUBLESHOOTING
Issue Possible Cause Remedy
Meter indicates higher flow than actual . Cavitation . Increase back pressure .
Meter indicates high flow . Dirt blocking flow area rotor . Clean meter; add filter .
Meter indicates low flow . Dirt dragging rotor . Clean meter; add filter .
Meter indicates low flow . Worn bearing . Replace bearing; recalibrate when
required .
Meter indicates low flow . Viscosity higher than calibrated . Change temperature; change fluid;
recalibrate meter .
Erratic system indication; meter alone
works well .
Ground loop is shielding . Ground shield one place only . Watch for
internal electronic instrument grounds .
Indicator shows flow when shut off .
Mechanical vibration causes rotor to
oscillate without turning .
Mechanical vibration . Isolate meter; use potted pickoff .
No flow indication . Full flow of fluid
opened into dry meter . Impact of fluid
on rotor causes bearing separation .
Fluid shock . New bearing failed . Move meter to position where it is full
of fluid at start-up .
Erratic indication at low flow; good
indication at high flow .
Low instrument sensitivity . 10
mV rms turbine signal is being
lowered by loading of electronics or
instrumentation cannot sense low level
signals .
Amplify signal .
No flow indication . Faulty pickoff . Replace pickoff; recalibrate as
necessary .
System works perfectly, except
indicates lower flow over entire range .
Bypass flow, leak . Eliminate bypass valves, leak . Faulty
solenoid valves .
Meter indicating high flow . Upstream
piping at meter smaller than meter .
Fluid jet impingement on rotor . Critical
in gas .
Change piping .
Opposite effects as above . Viscosity lower than calibrated . Change temperature; change fluid;
recalibrate meter .
Mass flow indication wrong . Turbine
meter is volumetric; density correction
is electronic; must change with
temperature .
Wrong fluid density . Critical in gas . Check fluid, electronics .
Erratic or wrong indication of flow . Loose pickoff . Tighten pickoff .
Indicates high flow two hours after
installing new bearing .
Bearing wear-in; small meters critical . Recalibrate . 20…30 min . run-in is
required to stabilize friction .
Cannot reach maximum flow rate;
meter selection was with Delta-P at 0 .75
sp . gr ., now using on 1 .0 sp . gr . Delta-P
is proportional to specific gravity .
High pressure drop . Install larger meter .
Does not repeat at low flows . Repeats at
high flows .
System resolution readability . Increase resolution, for example:
1 out of 100 = 1%
1 out of 1000 = 0 .1%
Table 1: Troubleshooting
Precision Meters, Turbine Flow Meters
Page 10 May 2014