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F05 Supply temperature high

Critical severity Elite EL

What the control is telling you

Supply water temperature too high. At or above 210 F the message shows and clears when below 194 F. Above 230 F it becomes a lockout with FAULT light and LOCKOUT flashing. Pump on.

Applies to: EL-80, EL-110, EL-150, EL-220, EL-299, EL-399 (N/LP)

Likely causes

  • Circulator not running or low flow
  • Boiler circulator pumping the wrong way
  • Supply thermistor fault

Test and repair steps

  1. Check circulator operation
  2. Confirm less than a 50 F rise from return to supply in the status menu
  3. Check the flow direction of the boiler circulator against the piping details
  4. Test the thermistor as for F02

Models that show this code

12 models in Elite EL

EL-110 LPEL-110 NEL-150 LPEL-150 NEL-220 LPEL-220 NEL-299 LPEL-299 NEL-399 LPEL-399 NEL-80 LPEL-80 N

Other codes on the same units

  • F01 Flue temperature switch / low water
  • F02 Supply sensor failure
  • F03 Return sensor failure
  • F04 Flue sensor failure
  • F06 Return temperature high
  • F09 No flame on ignition
  • F10 Flame loss
  • F11 False flame signal

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Source: Elite EL-80 N Installation Manual (LP-293), p. 70. 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.