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FlowMax · Combi boiler

E35 Flame detection fault (false flame)

High severity FlowMax condensing combi (FLOWMAX-90/120)

What the control is telling you

The board is detecting a flame signal when it should not, or the flame circuit is faulty.

Applies to: FLOWMAX-90, FLOWMAX-120

Likely causes

  • Ionization electrode faulty or dirty
  • Ionization electrode lead faulty
  • Control board faulty

Test and repair steps

  1. Turn off power and gas before removing the electrode.
  2. Inspect the ionization electrode; clean it, or replace it if damaged.
  3. Check the ionization lead and replace it if faulty.
  4. If the code remains, replace the control board.
  5. Warning: Gas work only by a qualified gas technician; leak-test all gas connections after any repair.

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Source: FlowMax FLOWMAX-120 Instruction Manual, 6.10 Troubleshooting table, p.66; FlowMax FLOWMAX-120 Instruction Manual, 6.11 Diagnostics error code list, p.67; FlowMax FLOWMAX-90 User Manual, Diagnostics - Error codes, p.8-9. 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.