HVACopediaFlowMax · Boiler · Other
Flue test and legionella functions
What happens, in order
- Hold the service button 7 seconds to start the flue test (code 07)
- Unit runs at maximum heating output with no modulation for 15 minutes for combustion testing
- Pressing the OFF button cancels the flue test
- Storage cylinder systems only every 7 days the control heats the cylinder to 60 C regardless of the DHW setpoint (legionella prevention, code 28)
Timings and thresholds
| Item | Value |
|---|---|
| Flue test duration | 15 min |
| Legionella interval | 7 days |
| Legionella temperature | 60 C |
Applies to: FLOWMAX-120
Models
FLOWMAX-120
More FlowMax boiler sequences
- Switch-on and mode selection · Startup
- Heating call with restart delay and pump overrun · Heating
- DHW call with pump overrun and priority · Domestic hot water
- Heating and DHW frost protection · Freeze protection
- Switched OFF at the control panel · Standby/shutdown
Related
Take it to the job
Sequences of operation, error codes and tips work offline in the HVACopedia app.
Source: FLOWMAX-120 installation manual (DIGITECH PCB SM20021, parameters 4-8, function codes 07/08/28). Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
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.