Vaillant ecoTEC plus 937 Instructions And Maintenance Instructions - page 46
Installation and maintenance instructions ecoTEC plus 0020031552_03
46
8 Troubleshooting
8.1
Logical fault finding procedure
Carry out the following checks before the actual trou-
bleshooting:
• Carry out the tests to check electrical safety (see Sec-
tion "Preparatory Checks on the Electrical System").
• Check that the external power supply for the combi
boiler is switched on and that there is a supply voltage
of 230 V AC between the connections "L" and "N".
• Check that the gas supply to the combi boiler is
switched on.
• Check that the combi boiler has been properly purged
and that there is a supply pressure of 20 mbar the
inlet to the boiler. (See Section "Gas Supply".)
• Check that the heating system is filled with water and
that there is a pressure of between 1.0 and 1.5 mbar.
Otherwise top up the system and bleed. (See Section
"Filling the Heating System".)
• Check that the stop valves in the flow and return lines
of the combi boiler are open.
• Check that the mains switch is set to "ON".
• Set the temperature of the central heating to "Maximum".
• Set the temperature of the hot water preparation to
"Maximum".
• Check that all external controllers are switched on
and are demanding heat (if no external controllers are
fitted, the connections 3 and 4 on the combi boiler
terminal must be connected together).
• Check that the burner anti-cycling time mode on the
combi boiler is not active.
8.1.1 Status
codes
The status codes which you can see in the display pro-
vide information concerning the current operating sta-
tus of the unit.
Proceed as follows to display the status codes:
Fig. 8.1 Display of status codes
• Press the "i" button.
The display shows the status code e.g. S.04 for the
"Burner mode - heating".
The status code display can be de-activated as follows:
• Press the "i" button. or
• Do not press any button for about 4 minutes.
The current heating flow temperature appears in the
display again.
Display
Meaning
Heating mode:
S.0
No heat demand
S.1
Fan running
S.2
Pump running
S.3
Ignition
S.4
Burner ignited
S.5
Fan and pump running
S.6
Fan over run
S.7
Pump overrun time
S.8
Anti-cycling mode
Hot water mode (ecoTEC plus 800 models only):
S.10
Hot water request
S.11
Fan running
S.13
Ignition
S.14
Burner ignited
S.15
Fan and pump running
S.16
Fan over-run
S.17
Pump over-run
Warm start mode/hot water storage tank charging:
S.20
Pump running
S.21
Fan running
S.23
Ignition
S.24
Burner ignited
S.25
Fan and water pump running
S.26
Fan over-run
S.27
Pump over-run time
S.28
Anti-cycling mode
All boilers:
S.30
No heat demand from external controllers (terminal
3-4 open)
S.31
Thermostat knob of central heating switched off or
no heat demand from an eBUS controller
S.32
Heat exchanger antifreeze active, as fan speed varia-
tion is too high. Appliance is within the waiting time
of the operation block function
S.34
Antifrost mode active
S.36
No heat demand from low voltage regulators (termi-
nal 7-8-9)
S.41
Water pressure >2.9 bar
S.42
Feedback from accessories module or defective con-
densate pump blocks the burner operation
S.53
Appliance is within the waiting period of the modula-
tion block/operation block function due to water
shortage (flow-return spread too large)
S.54
Appliance is within the waiting period of the operati-
on block function due to water shortage (tempera-
ture gradient)
S.96
Return flow sensor test, heat demands (hot water or
heating) are blocked
S.97
Water pressure sensor test, heat demands (hot water
or heating) are blocked
S.98
Flow/return flow sensor test, heat demands (hot
water or heating) are blocked
Table 8.1 Status codes (continuation see next page)
8 Troubleshooting