Troubleshooting 10; Logical Fault Finding Procedure; Status Codes; Diagnostic Codes - Vaillant ecoTEC plus Instructions For Installation And Servicing

10 Troubleshooting
10.1

Logical fault finding procedure

These checks must be carried out before attempting to
use the fault finding guide.
1. Carry out electrical safety checks (see section 4 'Wiring
system').
2. Check that the external electricity supply to the boiler
is on, and a supply of 230 V~ is present between boiler
terminals 'L' and 'N'.
3. Check that the gas supply to the boiler is on, that it
has been correctly purged and that an inlet pressure
of 20 mbar is available at the gas valve. (See section
5 'Gas Supply').
4. Ensure the heating system is full of water and the
system design pressure is attained. (sealed systems
only). If not, refill and vent the system. Ensure any flow
and return isolating valves (if fitted) are fully open.
5. Set the central heating temperature to maximum.
6. Set the domestic hot water temperature to maximum
(Only if additional Vaillant accessories are fitted).
7. Check that all external controls are on and calling for
heat (if no external controls are fitted, boiler terminals
3 and 4 must be linked). Check that the boiler anti
cycling economiser is not engaged.
10.1.1

Status codes

The status codes that you can see on the display provides
information about the current operating condition of the
appliance.
The display of the status codes can be called as follows:
• Press the "i" key.
The display shows the status code, e.g. S.4 for "Burner
mode - Heating". The display of the status codes can
be cancelled as follows:
• Press the "i" key.
• Do not press any key for approx. 4 minutes. The current
heating flow temperature appears in the display again.
Fig. 10.1 Display of status codes

10.1.2 Diagnostic codes

In the diagnostic mode, you can change certain parame-
ters or display more information. The diagnostic infor-
mation is divided into two diagnostic levels. The second
diagnostic level can be reached only after entering a
password.
Instructions for installation and servicing ecoTEC plus / 0020020828_05
Display Meaning
Heating mode (all models)
S. 0 No heat demand
S. 1 Fan running
S. 2 Water pump running
S. 3 Ignition sequence
S. 4 Burner ignited
S. 5 Fan and pump running
S. 6 Fan over run
S. 7 Pump over run
S. 8 Anti cycling mode
Domestic hot water mode (when accessories are fitted)
S.20 Warmstart demand
S.21 Fan running
S.22 Pump running
S.23 Ignition sequence
S.24 Burner ignited
S.25 Fan and water pump running
S.26 Fan over run
S.27 Pump over run
S.28 Anti cycling mode
Charge hot water cylinder (when accessories are fitted)
S.20 Warmstart demand
S.21 Fan running
S.22 Pump running
S.23 Ignition sequence
S.24 Burner ignited
S.25 Fan and water pump running
S.26 Fan over run
S.27 Pump over run
S.28 Anti cycling mode
All boilers:
S.30 No heating demand from external controls (clamp 3-4 open)
Central heating thermostat knob turned off or no
S.31
heat demand by the eBUS control unit
Heat exchanger antifreeze active, as fan speed varia-
S.32 tion is too high. Appliance is within the waiting time
of the operation block function
S.34 Anti frost mode active
S.36 No heating demand from low voltage controls (clamp 7-8-9)
S.41 Water pressure > 2,9 bar
Response from accessory module or defective conden-
S.42
sate pump is blocking burner operation
Appliance is within the waiting period of the operation block
S.53
function due to water shortage (VL-RL spread too big)
Appliance is within the waiting period of the operation block
S.54
function due to water shortage (temperature gradient)
Return-sensor check is running, demand (DHW or
S.96
heating) is blocked
Flow-/Return-sensor check is running, demand (DHW
S.98
or heating) is blocked
Table 10.1 Status codes

Troubleshooting 10

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