Thermon TraceNet TCM 18 - Manual (Page 71)

Permanent RTD sensors which enter the
insulation at 90 degrees may be more
sensitive to error associated with them de-
pending on insulation installation or how
well the sensor is physically attached. Ad-
just control set point to compensate for
any accuracy offset. When using a 90 de-
gree RTD probe for diagnostics, verify this
measurement technique on a known pipe
in the same general temperature range
and insulation configuration.
Damaged RTD sensor. Disconnect RTD sensor and measure re-
sistance. Compare to resistance tables
for corresponding value of temperature.
Compare to pipe or equipment tempera-
ture known by another probe or sensor.
If different, the RTD sensor may need re-
placement.
Heat tracing undersized, improperly in-
stalled or damaged. Review design/installation. Check heat
tracing for presence of proper current and
also meg for dielectric resistance. Repair
or replace heat tracing.
Heat tracing circuits are wired such that
the RTD for circuit A is controlling circuit
B, etc. Trace and recheck field and panel wiring.
Use circuit "turn -on " and "turn-off" tech-
nique or disconnect RTD’s one at a time to
see if the proper RTD failure alarm occurs
on the right circuit.
Heat tracing does not heat. Breaker has
been switched off due to maintenance ac-
tivities or has possibly malfunctioned. As soon as maintenance activities cease
and after conferring with operations man-
ager, switch breaker back ON. Note that
some period of time will elapse before the
temperature alarm goes away (pipes and
equipment take time to heat up).
67 PN 50316_0514