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Heating Cable Repair
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If IR is 20 MΩ or greater, skip the following two steps and
continue with the step (prior to Figure 14) to measure the
outside diameter of the cables. If IR is still low after drying
out the MI heating cable, continue with the additional
steps following.
If IR is still low, it will be necessary to temporarily remove
a longer section of corrugate so that the inner MI heating
cable can be heated out. Use the tube cutter to cut the
corrugate an additional 10 in (25 cm) back from the end.
This will expose an extra 10 in (25 cm) of the MI heating
cable. Do not discard the corrugate; it will be reused after
the moisture has been removed from the MI heating
cable (see Appendix D on removing moisture from the
MI cable).
Once the MI heating cable is heated out and IR is at an
acceptable value, slide a corrugate union (only required
if an extra 10″ of corrugate was removed) and the 10 in
(25 cm) section of corrugate back onto the heating
cable. Prior to fitting the parts together, polish both ends
of the corrugate and the corrugate union with the nylon
mesh sanding pad (Figure 12). The surfaces must be
clean for the silver braze to adhere to them. Next, using
flux brush, apply flux to the ends of the corrugate and
the corrugate union. Fit the parts together so that both
ends of the corrugate butt against the center-stop in the
corrugate union (Figure 12).
Corrugate
union
Nylon mesh sanding pad
10” (25 cm) section
of corrugate
Figure 12: Polish corrugate and corrugate union
