Checking The Pre-Charge Pressure Of The External Expansion Vessel; Completing Inspection And Maintenance Work; Checking The Product For Leak-Tightness; Troubleshooting 9 - Vaillant ecoTEC plus VU GB 656/4-5 A Installation And Maintenance Instructions Manual

8.11 Checking the pre-charge pressure of the
external expansion vessel
1. Depressurise the heating installation.
2. Measure the pre-charge pressure of the expansion ves-
sel at the vessel valve.
3. Fill the expansion vessel with air at a pre-charge pres-
sure of less than 0.075 (0.75 bar) according to the static
head of the heating installation.
4. If water escapes from the valve of the expansion ves-
sel, you must replace the expansion vessel.
8.12 Completing inspection and maintenance
work
▶
Check the CO₂ content and, if necessary, adjust it (air
index setting). (→ Page 21)
▶
Check the CO₂ content and, if necessary, adjust it (air
index setting). (→ Page 21)
▶
If required, reset the maintenance interval (→ Page 24).
8.13

Checking the product for leak-tightness

▶
Check that the product is leak-tight. (→ Page 22)
9 Troubleshooting
You can find an overview of the fault codes in the appendix.
Overview of fault codes (→ Page 35)
9.1

Contacting your service partner

If you contact your service partner, if possible, please men-
tion
–
the fault code that is displayed (F.xx),
–
the product status (S.xx) that is displayed.
9.2

Calling up status codes

You can find an overview of the status codes in the
appendix.
Status codes – Overview (→ Page 34)
▶
To call up the display of the status codes, press
◁
The display shows the status code, e.g. S.4 for
"Burner mode: Heating".
▶
To exit the status codes display, press
any button for approximately four minutes.
◁
Depending on the settings, the current flow temperat-
ure or current water pressure of the heating installa-
tion reappears in the display.
0020214491_01 ecoTEC plus Installation and maintenance instructions
9.3

Reading off the fault codes

If a fault develops in the product, the display shows a fault
code F.xx.
Fault codes have priority over all other displays.
If multiple faults occur at the same time, the display shows
the corresponding fault codes for two seconds each in se-
quence.
▶
Rectify the fault.
▶
To restart the product, press
tions).
▶
If you are unable to rectify the fault and the fault recurs
despite several reset attempts, contact Customer Ser-
vice.
9.4

Querying the fault memory

The product has a fault memory. You can use this to query
the last ten faults that occurred in chronological order.
▶
Press
faults that occurred.
Overview of fault codes (→ Page 35)
▶
Use
▶
To exit the fault memory display, press
press any button for approximately four minutes.
◁
Depending on the settings, the current flow temperat-
ure or current water pressure of the heating installa-
tion reappears in the display.
9.5

Performing diagnostics

▶
You can use the diagnostics codes (→ Page 23) during
fault diagnostics to change individual parameters or to
display further information.
9.6

Using check programmes

▶
You can also use the check programmes (→ Page 16)for
troubleshooting.
9.7

Resetting parameters to factory settings

▶
To simultaneously reset all parameters to the default
settings, set D.96 to 1.
.
9.8

Preparing the repair work

1. Decommission the product.
or do not press
2. Disconnect the product from the power mains.
3. Remove the front casing. (→ Page 10)
4. Close the gas isolator cock.
5. Close the service valves in the heating flow and in the
heating return.
6. Close the service valve in the cold water pipe.
7. Drain the product if you want to replace water-bearing
components of the product.
8. Make sure that water does not drip on live components
(e.g. the electronics box).
9. Use only new seals.

Troubleshooting 9

(→ Operating instruc-
and at the same time to display the last ten
to scroll back in the fault memory.
or do not
29