Rinnai · Wall furnace

14 Overheat (fusible link)

Critical severity EX DT

What the control is telling you

The overheat safety tripped. The fusible link is a one-time safety device that breaks to shut the furnace off when it overheats.

Applies to: Rinnai EnergySaver direct vent wall furnaces EX08DT, EX11DT, EX17DT, EX22DT

Likely causes

  • Dirty air filter restricting airflow
  • Underlying overheating condition that must be found

Test and repair steps

  1. Clean the air filter.
  2. Turn the furnace off and back on with the ON/OFF button to try to clear the code.
  3. If it repeats, a qualified service agency must find the cause of the overheat before anything is replaced.
  4. A blown fusible link may only be replaced by a qualified service agency, after the cause is corrected.

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Source: Rinnai EX08DT/EX11DT and EX17DT/EX22DT Installation and Operation Manuals (200000083, 200000084), Table 9 'Diagnostic Codes', p.35–36. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

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.