C Fault Codes/Limp Home Mode Codes; D Troubleshooting - Vaillant ecoTEC plus VU Series Operating Instructions Manual

Code
S.020
S.022
S.023
S.024
S.026
S.027
S.028
S.031
S.034

C Fault codes/limp home mode codes

Note
The code table only shows an extract of the entire code. If fault codes or limp
home mode codes other than those listed are displayed, action by a competent
person is required.
Code/meaning
F.022
No/insufficient water
in the product or the
water pressure is too
low.
F.028
The flame signal was
not detected during
the ignition phase.

D Troubleshooting

Symptom
Product does not start
up (no hot water,
heating remains cold)
20
Meaning
There is no demand for the domestic hot water cylinder charging.
The domestic hot water cylinder charging is active and the pump is in
prerun mode.
The domestic hot water cylinder charging is active and the unit ignites.
The domestic hot water cylinder charging is active and the burner is
operating.
The domestic hot water cylinder charging is active and the fan is in
overrun mode.
The domestic hot water cylinder charging is active and the heating
pump is in overrun mode.
The domestic hot water cylinder charging is active and the unit is in
burner anti-cycling time.
Heating mode has been deactivated and there is no domestic hot water
demand.
The frost protection function is active.
Possible cause
Water deficiency in
the heating installation
After five unsuccessful
ignition attempts, the
product has switched
to fault mode.
Possible cause
The gas isolator cock
installed on-site and/or
the gas isolator cock
on the product is
closed.
The power supply in
the building is discon-
nected.
Measure
1. Check the filling pressure of the heating
installation. (→ Section 5.4.1)
2. Top up with heating water.
(→ Section 5.4.2)
1. Check whether the gas stopcock is open.
2. Press the reset button for longer than
three seconds.
– Maximum number of repetitions: 3
3. If you are unable to eliminate the ignition
fault, contact a competent person.
Measure
▶
Open both gas isolator cocks.
▶
Check the fuse in the building. The product
automatically switches back on when the
power supply is restored.
Operating instructions 0020308119_02