Vaillant ecoTEC plus VU 446/5-5 (H-GB) Installation And Maintenance Instructions Manual page 61

Code/meaning
F.28
Ignition unsuccessful
F.29
Ignition and check faults during
operation – flame has gone out
F.32
Fan fault
F.33
Air pressure switch fault
F.49
Fault: eBUS
0020261389_03 ecoTEC plus Installation and maintenance instructions
Possible cause
Gas flow pressure too low
The thermal isolator device has
been triggered
Cable connections not plugged
in/loose
Ignition system defective
PCB defective
Ionisation flow interrupted
Earthing defective
Air in the gas supply
Gas meter defective
Gas supply is interrupted
Flue gas circulation is incorrect
Ignition misfire
Diagnostics code D.085 incor-
rectly set
Condensate siphon blocked
Gas valve assembly defective
Gas meter defective
The gas pressure monitor has
been triggered
Air in the gas supply
Gas flow pressure too low
The thermal isolator device has
been triggered
Cable connections not plugged
in/loose
Ignition system defective
Ionisation flow interrupted
Earthing defective
PCB defective
Plug on fan not plugged in or is
loose
Multiple plug loose/not plugged
in
Interruption in the cable harness
Fan blocked
Electronics defective
Air/flue pipe blocked
Defective air pressure switch
Cable connections not plugged
in/loose
Fan defective
PCB defective
Excessive counter-pressure in
the air/flue pipe
eBUS overload
Short circuit in the eBUS con-
nection
Different polarities at the eBUS
connection
Measure
▶
Check the gas flow pressure.
▶
Check the thermal isolator device.
▶
Check the cable connections.
▶
Replace the ignition system.
▶
Replace the PCB.
▶
Check the monitoring electrodes.
▶
Check the product's earthing.
▶
Check the gas-air ratio.
▶
Replace the gas meter.
▶
Check the gas supply.
▶
Check the air/flue system.
▶
Check that the ignition transformer works correctly.
▶
Using an installation with a flue non-return flap, check
whether the diagnostics code D.085 has been set correctly.
(→ Page 28)
1. Check whether the condensate discharge is connected cor-
rectly. (→ Page 25)
2. If the drain is blocked, check whether the heat exchanger's
internal insulating material is OK.
▶
Replace the gas valve assembly.
▶
Replace the gas meter.
▶
Check the gas flow pressure.
▶
Check the gas-air ratio.
▶
Check the gas flow pressure.
▶
Check the thermal isolator device.
▶
Check the cable connections.
▶
Replace the ignition system.
▶
Check the monitoring electrodes.
▶
Check the product's earthing.
▶
Replace the PCB.
▶
Check the plug on the fan and the plug connection.
▶
Check the multiple plug and plug connection.
▶
Check the cable harness.
▶
Check that the fan works correctly.
▶
Check the PCB.
▶
Check the entire air/flue pipe.
▶
Replace the air pressure switch.
▶
Check the cable connections.
▶
Check that the fan works correctly.
▶
Replace the PCB.
1. Ensure that there is no risk of excessive counter-pressure.
2. If required, protect the product (wind guard, cascade lines
with a larger diameter, etc.).
▶
Check that the eBUS connection works correctly.
▶
Check that the eBUS connection works correctly.
▶
Check that the eBUS connection works correctly.
61