Thermon TraceNet TCM 18 - Manual (Page 76)

Heat tracing cable may have been ex-
posed to temperatures in excess of their
maximum temperature ratings (excessive
steam-out temperatures or upset process
temperature events) and could have dam-
aged the heater. Replace heater.
Controller may be in error in reading cur-
rent. Use a different current clamp type meter
which is known to be accurate and do a
comparative reading. If the current mea-
suring circuitry is in error, investigate con-
trols further. Note that one should only
read heater currents when the heater is
100% on.
Heater circuit may be shorter than antici-
pated in the design stage. Verify installed length (if possible) and if
different review design. If length is differ-
ent but performance-wise the “as built” de-
sign is acceptable, initiate “as built” draw-
ing change and change controller low cur-
rent setting.
Check heater set tags or
markings on heater cable against instal-
lation drawings. As an additional check,
disconnect heater from power and mea-
sure DC resistance.
Wrong heater wattage or heater resis-
tance may be installed. Measure pipe temperature and measure
steady-state heater current, voltage, and
length. Compare to manufacturer’s rated
power curve. Replace heat tracing cable
if necessary.
Heat tracing may be powered on wrong
voltage. Recheck heater supply voltage.
Current sensing circuitry may have en-
countered a problem. Use a different current clamp type meter
which is known to be accurate and do
a comparative reading. Investigate cur-
rent measurement circuitry further. Note
that one should only read heater currents
when the heater is 100% on.
PN 50316_0514 72