Vaillant ecoTEC plus SERIES Installation And Maintenance Instructions Manual - page 49
Appendix
0020209593_01 ecoTEC plus Installation and maintenance instructions
49
Code
Meaning
Cause
F.12
Short circuit at cylinder charging sensor
(NTC) only in combination with F.91
NTC defective, short circuit in cable harness, cable/casing
F.13
Product with integrated hot water
generation: Short circuit warm start
sensor/cylinder sensor
Product with integrated hot water genera-
tion and actoSTOR: Short circuit cylinder
sensor (NTC) only in combination with F.91
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
F.25
Safety switch-off: Flue gas temperature too
high
Break in plug connection for optional flue gas safety temperature limiter
(STB), break in cable harness
F.26
Fault: Gas valve without function
Gas valve stepper motor not connected, multiple plug on the PCB not
plugged in correctly, interruption in cable harness, gas valve stepper
motor defective, electronics defective
F.27
Safety switch-off: Flame simulation
Moisture on the electronics, electronics (flame monitor) defective, gas
solenoid valve leaking
F.28
Failure during start-up: Ignition unsuccess-
ful
Gas meter defective or gas pressure monitor has triggered, air in gas,
gas flow pressure too low, thermal isolator device (TAE) has triggered,
condensate duct blocked, incorrect gas restrictor, incorrect spare part
gas valve, fault on the gas valve, multiple plug on PCB incorrectly
plugged in, break in cable harness, ignition system (ignition transformer,
ignition cable, ignition plug, ignition electrode) defective, ionisation
current interrupted (cable, electrode), incorrect earthing of product,
electronics defective
F.29
Failure during operation: Re-ignition unsuc-
cessful
Gas supply temporarily stopped, flue gas recirculation, condensate duct
blocked, defective earthing of product, ignition transformer has spark
failure
F.32
Fan fault
Plug on fan not correctly plugged in, multiple plug on PCB not correctly
plugged in, break in cable harness, fan blocked, Hall sensor defective,
electronics defective
F.42
Coding resistance fault (possible in combin-
ation with F.70)
Short circuit/interruption in output range coding resistance (in cable
harness at heat exchanger) or gas group resistor (on PCB)
F.49
Fault: eBUS
Short circuit on eBUS, eBUS overload or two power supplies with differ-
ent polarities on the eBUS
F.52
Contact fault mass flow sensor/Venturi
The mass flow sensor/Venturi is not connected electrically
–
The plug is not plugged in correctly
–
The plug is not plugged in
–
The plug is defective
–
The slot is defective (loose connection)
–
Mass flow sensor/Venturi defective
F.53
Combustion regulation fault
The combustion regulation has detected a fault
–
Gas flow pressure too low
–
Liquid gas coding resistance used when operating with natural gas
–
If the fault occurs again after being cleared:
–
Gas valve defective
–
Mass flow sensor/Venturi defective, wet or blocked (if the fault
occurs again after being cleared): Do not wet the sensor, do not
use any lubricants on the O-ring on the Venturi.