SEFRAM MW9520 Manuel D'utilisation page 55

(b) Tracing an underground circuit:
The circuit to be measured must not be live.
Connect the MW9520-E as show in the figure.
The MW9520-E must be correctly earthed.
Select the automatic mode of MW9520-R to
find and trace the circuit.
The distance between the earth wire and
the circuit to be located must be as long as
possible, otherwise the circuit cannot be located
precisely.
(c) Detection of faults in an in floor heating system:
The circuit measured must not be live, then
the right end of circuit is connected to the
transmitter that is sending "F" code signal, and
the left end of circuit is connected to the other
transmitter that is sending "C" code signal, and
the both transmitters must be earthed. When
the line is traced, the place at which the signal
received by the receiver falls off suddenly is the
location of the break.
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