Appendix
0020214491_01 ecoTEC plus Installation and maintenance instructions
35
Status code
Meaning
S.24
DHW mode: Burner on
S.25
DHW mode: Pump/fan overrun
S.26
DHW mode: Fan overrun
S.27
DHW mode: Pump overrun
S.28
Hot water burner anti-cycling time
Special cases
S.30
Room thermostat (RT) is blocking heating mode
S.31
Summer mode active or no heat requirement
from eBUS controller
S.32
Waiting period because of fan speed deviation
S.34
Frost protection mode active
S.36
Reference setting for the continuous controller 7-
8-9 or eBUS controller is < 20 °C and blocks the
heating mode
S.39
Contact thermostat tripped
S.41
Water pressure > 0.28 MPa (2.8 bar)
S.42
Flue non-return flap return signal blocks burner
operation (only in connection with accessories)
or condensate pump faulty, heat requirement is
blocked.
S.53
Product is within the waiting period of the mod-
ulation block/operation block function as a res-
ult of low water pressure (flow/return spread too
large)
S.54
Product is within the waiting period of the oper-
ation blocking function as a result of low water
pressure (temperature gradient)
S.59
Waiting period: Minimum volume of circulation
water not achieved
S.85
Service message: "Check circulation water
quantity".
S.96
Return sensor test running, heating demands are
blocked.
S.97
Water pressure sensor test running, heating de-
mands are blocked.
S.98
Flow/return sensor test running, heating de-
mands are blocked.
D
Overview of fault codes
Code
Meaning
Cause
F. 0
Flow temperature sensor interruption
NTC plug not plugged in or has come loose, multiple plug on the PCB
not plugged in correctly, interruption in cable harness, NTC defective
F. 1
Return temperature sensor interruption
NTC plug not plugged in or has come loose, multiple plug on the PCB
not plugged in correctly, interruption in cable harness, NTC defective
F.10
Flow NTC short circuit
NTC defective, short circuit in cable harness, cable/casing
F.11
Return NTC short circuit
NTC defective, short circuit in cable harness, cable/casing
F.13
Cylinder temperature sensor short circuit
NTC defective, short circuit in cable harness, cable/casing
F.20
Safety switch-off: Temperature limiter
Incorrect earth connection between cable harness and product, flow or
return NTC defective (loose connection), black discharge via ignition
cable, ignition plug or ignition electrode
F.22
Safety switch-off: Low water pressure
No or insufficient water in the product, water pressure sensor defective,
cable to pump or water pressure sensor loose/not connected/defective
F.23
Safety switch-off: Temperature difference too
great
Pump blocked, insufficient pump output, air in product, flow and return
NTC connected the wrong way round
F.24
Safety switch-off: Temperature rise too fast
Pump blocked, insufficient pump output, air in product, system pressure
too low, non-return valve blocked/incorrectly installed
