Vaillant ecoTEC plus 418 - Page 94

Domestic hot water mode (when accessories are fitted)
S.20
Warmstart demand
S.21
Fan running
S.22
Pump running
S.23
Ignition sequence
S.24
Burner ignited
S.25
Fan and water pump running
S.26
Fan over run
S.27
Pump over run
S.28
Anti cycling mode
Charge hot water cylinder (when accessories are fitted):
S.20
Warmstart demand
S.21
Fan running
S.22
Pump running
S.23
Ignition sequence
S.24
Burner ignited
S.25
Fan and water pump running
S.26
Fan over run
S.27
Pump over run
S.28
Anti cycling mode
All boilers:
S.30
No heating demand from external controls (clamp 3-4 open)
S.31
Central heating thermostat knob turned off or no heat demand by the eBUS
control unit