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FlowMax · Combi boiler

E14 Air pressure switch tripped

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

What the control is telling you

Listed only in the 120 diagnostics list. The 120 troubleshooting table puts air pressure switch faults under E02 instead; checks below come from that E02 entry.

Applies to: FLOWMAX-90, FLOWMAX-120

Likely causes

  • Air pressure switch faulty
  • Intake or exhaust vent blocked
  • Air pressure switch wiring loose

Test and repair steps

  1. Inspect the intake and exhaust vent pipes and terminals for blockage and clear them.
  2. Check the vent length is within the 100 ft maximum equivalent length (each 90° short elbow = 7.5 ft, each 45° = 2.5 ft).
  3. Check the air pressure switch wiring and sensing hoses.
  4. Replace the switch if it does not close with the fan running and venting clear.

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Source: FlowMax FLOWMAX-120 Instruction Manual, 6.11 Diagnostics error code list, p.67. 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.