Diagnostic Codes - Vaillant ecoTEC plus 937 Instructions For Installation And Servicing

8 Troubleshooting
Display Meaning
Hot water mode:
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 overrun
Warm start mode/hot water storage tank charging:
S.20 Warm start function demand
S.21 Fan running
S.22 Pump running
S.23 Ignition
S.24 Burner ignited
S.25 Fan and water pump running
S.26 Fan over run
S.27 Pump overrun 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
variation 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
(terminal 7-8-9)
S.41 Water pressure >2.9 bar
S.42 Feedback from accessories module or defective
condensate pump blocks the burner operation
S.53 Appliance is within the waiting period of the
modulation block/operation block function due to
water shortage (flow-return spread too large)
S.54 Appliance is within the waiting period of the operation
block function due to water shortage (temperature
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)
52
8.1.2

Diagnostic codes

In the diagnostic mode, you can change certain
parameters or display more information.
The diagnostic information is divided into two diagnostic
levels. Access to the second diagnostic level can only be
permitted after entering a password.
Caution!
a
Danger of incorrect operation and wrong unit
parametrisation!
Access to the second diagnostic level must be
used exclusively by a heating engineer.
First diagnostic level
• Press the "i" and "+" buttons simultaneously.
The display shows "d.00".
• Use the buttons "+" or "–" to move to the desired
diagnostic number of the first diagnostic level (see the
Table 8.2).
• Press the "i" button.
The associated diagnostic information is shown in the
display.
• If necessary you can change the value with the
buttons "+" or "–" (display flashing).
• Save the new value by holding down the "i" button for
approx. 5 seconds until the display no longer flashes.
You can end the diagnostic mode as follows:
• Press the "i" and "+" buttons simultaneously.
or
• Do not press any button for about 4 minutes.
The current heating flow temperature appears in the
display again.
ecoTEC plus 937 installation and maintenance manual