21
User’s Guide 2014
Testing of Flowtube
Always switch off power source before connecting and disconnecting cables.
Use a multimeter to measure
voltage at coil terminals of
flowtube.
Approx 50% of supply voltage
Signal converter faulty or wiring problem
investigate.
Switch off signal converter.
Disconnect electrode wires from
terminals on flowtube with
flowtube empty. Measure the
resistance between each
electrode terminal and ground on
the flowtube <500k
Ω?
Are measured resistance
>10Mohm?
Break or short-circuit in field coil cable.
Correct problem.
Electrodes leaking return flowtube for
repair.
Disconnect wires from coil
terminals of signal converter. Test
insulation between coil wires of
cable and Gnd terminal on signal
converter.
Is resistance > 20M
Ω?
Disconnect cable from coil terminals of
flowtube. Test insulation between coil
terminals of flowtube and ground (body of
flowtube).Is resistance >20M
Ω?
Is resistance > 20M
Ω?
Disconnect coil wires from
terminals of flowtube. Measure
the resistance between terminals..
Is it approx. 40Ω? Measure
resistance between terminal and
ground. Is resistance >20M
Ω.
Cable has ground fault.
Replace!
Field coils faulty
Flowtube in order
Flowtube defective! Return for repair
No
Yes
Yes
Yes
Yes
No
No
Yes
No
Yes
Check power to signal converter.Is led on
triac on?
No
Yes
No
