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FlowMax · Combi boiler

E12 DHW storage tank (cylinder) sensor fault

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

What the control is telling you

Only on units set up to heat an indirect storage tank (parameter 1 = 01 or 02). The tank sensor reads out of range; sensor is 10 kOhm at 25°C. Lead may be up to 8 m long.

Applies to: FLOWMAX-90, FLOWMAX-120

Likely causes

  • Tank sensor faulty or wrong type
  • Tank sensor wire disconnected or wet

Test and repair steps

  1. Confirm the unit is configured for a storage tank (parameter 1) - if no tank is installed, the setting may be wrong.
  2. Check the tank sensor lead and connection at the board; maximum lead length is 8 m.
  3. Measure the sensor about 10 kOhm at 25°C (77°F).
  4. Replace the sensor if faulty or incorrect.
  5. Restart and confirm the code clears.

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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. Summarized in our own words; check the original manual for your model.

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