Test Procedures
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• Allow the system to reach the control point. This
may take up to four hours for most circuits. Large,
liquid-filled pipes may take longer.
• Measure the voltage, amperage, and pipe
temperature for each circuit and record the values
in the “Installation and Inspection Record” (refer to
Section 11). This information is needed for future
maintenance and troubleshooting.
• When the system is completely checked out, reset the
thermostat to the proper temperature.
Control and monitoring systems
Refer to the installation instructions supplied with the
product for commissioning tests and records.
9.4 Fault Location Tests
FAULT LOCATION
There are three methods used for finding a fault within a
section of heating cable: the ratio method, 1/R method,
and the capacitance method. The capacitance method
can also be used to determine total heating cable length.
RATIO TEST METHOD
a.) To locate bus wire short:
The ratio method uses resistance measurements taken at
each end of the heating cable to approximate the location
of a bus wire short. A shorted heating cable could result
in a tripped circuit breaker or a cold section of pipe.
Measure the bus-to-bus conductor resistance
from
the front end (measurement A) and the back end
(measurement B) of the suspected section.
A
B
A
B
A
B
Braid
