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ICP · Furnace

7 Limit circuit lockout

High severity ICP (F/G)9MAE Modulating Furnace

What the control is telling you

Limit or rollout switch open more than 3 minutes, or 10 limit trips in a row at maximum heat. Auto-resets after 3 hours. Troubleshoot as code 4.

Applies to: ICP F9MAE / G9MAE modulating variable-speed condensing gas furnaces (060, 080, 100, 120 kBtu/h)

Likely causes

  • Same causes as code 4 - airflow restriction, blower problem, overfiring, failed limit/rollout

Test and repair steps

  1. Warning: Find why the limit/rollout opened before resetting - repeated trips mean overheating.
  2. Follow code 4 checks filter, ducts, blower wheel, gas input, limit switch and gasket.
  3. Manually reset rollout switch if tripped.

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Source: ICP (F/G)9MAE Service and Technical Support Manual 440 04 4700 00, Figure 16 Troubleshooting Chart, p.35. Summarized in our own words; check the original manual for your model.

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For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.