Carpet

Seaming Iron Not Heating or Overheating

Diagnosing a seaming iron that won't heat or runs too hot: settings, cords, thermostats and elements, and what overheating does to seams.

Updated · 2 min read

A seaming iron that won't heat stops the job, and one that runs hot quietly ruins seams. Most of the time the cause is the setting, the extension cord or the thermostat. The specs below come from iron makers' documentation.[1][2]

Safety

Unplug the iron and let it cool before any inspection. If the housing, cord or plug is damaged, stop using it until it's repaired.

Know your settings

You can't tell whether an iron runs too hot without knowing what the dial means.

  • On the Crain No. 905, dial setting 1 is 220°F, 2 is 290°F, 3 is 360°F, 4 is 420°F. The red light goes off at temperature.[1]
  • The Crain No. 945 holds within 15°F either way, from 240 to 420°F.[4]
  • The Taylor 890 shows a red light for power and heat, and green at temperature.[5]
  • Settings vary by iron and tape.[3] Follow the tape's instructions.

Iron won't heat

Work from the outlet in.

  1. Try a different outlet and a different extension cord. Use cords rated for 10 amps.[1]
  2. Check the power light. No light usually means power, cord or switch.
  3. Inspect the cord for cuts and the plug for damage. The Crain replacement cord is 1905-32.[1]
  4. If it lights but never reaches temperature, suspect the thermostat (Crain 1905-15) or the thermal breaker (1905-16).[1]
  5. If it lights and stays cold, suspect the heating element (Crain 1920-A for 120V).[1]

Iron runs too hot

Overheating is the more common complaint, and it shows in the seam.

  • Overheating synthetic backings shrinks and discolors them.[1]
  • For Roberts Heat Bond tapes on the 10-282G-2, 10-286G and 10-482G, start at 2 to 3 on the dial; for other tapes, check with the tape maker.[2]
  • Check the dial first. If the iron still runs hot on a low setting, the thermostat is suspect.
  • Always use a heat shield.[3]

Plate care

A dirty plate heats unevenly and drags. Never clean the plate with metal or sharp tools.[1] Wipe off tape adhesive while it's warm with a cloth or the cleaning method the maker specifies.

Common mistakes

These cause most seam damage blamed on the iron.

  • Undersized extension cords. The iron heats slowly and unevenly.
  • Cranking the heat to go faster. The backing scorches.
  • No heat shield.
  • Scraping the plate with a knife.

Seaming technique is in Hot-melt seaming.

Irons we carry

These are the irons and seam tools we stock.

References

  1. Crain No. 905 manual
  2. Roberts: Heat bond iron owner's manual (10-282G-2, 10-286G, 10-482G)
  3. CRI 105: Hot-melt seaming
  4. Crain No. 945 electronic heat bond iron (product page)
  5. Taylor 890 seaming iron (product page)

Linked PDF documents are archived copies saved by PreFloor Tools so they stay available if the publisher moves or removes them. Check the publisher's website for the latest revision.

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