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Following are Diagnostics codes from the Vaillant Manuals.

StatuscodeLinkStatusMeaningApplicable to
S.00Heating: No heat de- mandHeating has no heat demand. The burner is off.Heating mode (all models)
S.01Heating mode: Fan start- upThe fan start-up for heating mode is activated.Heating mode (all models)
S.02Heating mode: Pump pre-runThe pump prerun for heating mode is activated.Heating mode (all models)
S.03Heating mode: IgnitionThe ignition for heating mode is activated.Heating mode (all models)
S.04Heating mode: Burner onThe burner for heating mode is activated.Heating mode (all models)
S.05Heating mode: Pump/fan overrunThe pump/fan overrun for heating mode is activated.Heating mode (all models)
S.06Heating mode: Fan over- runThe fan overrun for heating mode is activated.Heating mode (all models)
S.07Heating mode: Pump overrunThe pump overrun for heating mode is activated.Heating mode (all models)
S.08Heating mode: Anti-cyc- ling timeThe anti-cycling time for heating mode is activated.Heating mode (all models)
S.10DHW demandThe domestic hot water demand is activated.Domestic hot water mode (ecotec combination boilers only)
S.11DHW mode: Fan start-upThe fan start-up for domestic hot water mode is activated.Domestic hot water mode (ecotec combination boilers only)
S.13DHW mode: IgnitionThe ignition for domestic hot water mode is activated.Domestic hot water mode (ecotec combination boilers only)
S.14DHW mode: Burner onThe burner for domestic hot water mode is activated.Domestic hot water mode (ecotec combination boilers only)
S.15DHW mode: Pump/fan overrunThe pump/fan overrun for domestic hot water mode is activated.Domestic hot water mode (ecotec combination boilers only)
S.16DHW mode: Fan overrunThe fan overrun for domestic hot water mode is activated.Domestic hot water mode (ecotec combination boilers only)
S.17DHW mode: Pump over- runThe pump overrun for domestic hot water mode is activated.Domestic hot water mode (ecotec combination boilers only)
S.20DHW demandThe domestic hot water demand is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.21DHW mode: Fan start-upThe fan start-up for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.22DHW mode: Pump pre- runThe pump prerun for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.23DHW mode: Ignition Burner onThe ignition for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.24DHW mode:The burner for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.25DHW mode: Pump/fan overrunThe pump/fan overrun for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.26DHW mode: Fan overrunThe fan overrun for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.27DHW mode: Pump over- runThe pump overrun for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.28DHW anti-cycling timeThe anti-cycling time for domestic hot water mode is activated.Warm start (ecotec combination boilers only) / Charge hot water cylinder (ecotec systems boilers only)
S.30No heat demand: Con- trollerRoom thermostat blocks heating mode.All boilers
S.31No heat demand: Sum- mer modeSummer mode is activated; there is no heat demand.All boilers
S.32Waiting time deviation: Fan speedThe waiting period for the fan start-up is activated.All boilers
S.34Heating mode: Frost pro- tectionThe frost protection function for heating mode is activated.All boilers
S.39Contact thermostat triggeredThe surface-mounted thermostat or the condensate pump has triggered.All boilers
S.40Comfort protection act- iveThe comfort protection mode is activated.All boilers
S.41Water pressure too highThe system pressure is too high.All boilers
S.42Flue non-return flap closedFlue non-return flap return signal blocks burner operation (only in conjunction with the multi-functional module) or condensate pump defective, heat demand is blocked. All boilers
S.46Comfort protection: Min- imum load, loss of flame
Comfort protection mode for flame loss at minimum load is activated.All boilers
S.53Waiting time: Water shortageThe product is within the waiting period of the modulation block/operating block function as a result of a water deficiency (flow/return spread too large).All boilers
S.54Waiting time: Water shortageProduct is in the waiting period of the operation blocking function as a result of low water pressure (temperature gradient).All boilers
S.57Waiting time: Measuring programThe product is within the waiting period as a result of the measuring programme.
All boilers
S.58Burner modulation limit- ationThe burner modulation limitation is activated.
All boilers
S.61Fault: Incorrect gas typeThe coding resistor on the PCB does not match the entered gas group (see also F.92)All boilers
S.62Adjust CO2Set the CO2 content.All boilers
S.63Fault: Check gas routeA fault message is activated. Check the gas route.All boilers
S.76Service message: Check water pressureA service message is activated. Check the water pressure.All boilers
S.88Purging programme is runningThe purge programme is activated.All boilers
S.92Water circulation volume self-testThe self-test for the water circulation volume is activated.All boilers
S.93Flue gas measurement not possible
Flue gas analysis is not currently possible.All boilers
S.96Return temperature sensor self-testThe self-test for the return temperature sensor is activated.All boilers
S.97Water pressure sensor self-testThe self-test for the water pressure sensor is activated.All boilers
S.98
Flow/return temperature sensor self-testThe self-test for the flow/return temperature sensor is activated.All boilers
S.99Vaillant self-testThe Vaillant self-test is activated.All boilers

status codes

 D Codes

CodeParameter / MeaningDisplay Values / adjustable value or explanationsFactory settingOwn settingArticle Page / Links 
D.000Heating partial loadAdjustable partial heat load in kW
Auto: Product automatically adjusts max. partial load to current system demand
Auto
D.001Pump overrun: Heating1 to 60 min5 min
D.002Max. anti-cycl. time: Heating2 to 60 min20 min
D.003Outlet temperature actual valueIn °CNot ad- justable
D.004Cylinder temperature actual valueIn °CNot ad- justable
D.005Heating target flow temperatureIn °C; the maximum value that is set in D.071 and is restricted by means of an eBUS control if such a control is connectedNot ad- justable
D.006Outlet temperature target value35 to 65 °CNot ad- justable
D.007Comfort mode target value
APC target value
Cylinder temperature target value
Product with integrated domestic hot water generation, and product with integrated domestic hot water genera- tion and shift-load cylinder
35 to 65 °C
Product with heating mode only
Frost protection is at 15 °C, then 40 to 70 °C (max. temperature can be adjusted under D.020)
Not ad- justable
D.008Controller 3-4Room thermostat open (no heat requirement) Room thermostat closed (heat requirement)Not ad- justable
D.009eBUS controller target valuen °C
Not ad- justable
D.010Internal pumpOn, OffNot ad- justable
D.011External pumpOn, OffNot ad- justable
D.012Cyl. charging pumpOn, OffNot ad- justable
D.013Circulation pumpOn, OffNot ad- justable
D.014Pump speed target valueTarget value of internal high-efficiency pump in %. Pos- sible settings:
0 = Auto 1 = 53
2 = 60
3 = 70
4 = 85 5 = 100
0 = Auto
D.015Pump speed actual valueActual value for internal high-efficiency pump in %Not ad- justable
D.016Controller 24 V DC: Heating mode
Heating mode off/onNot ad- justable
D.017Control typeControl type:
0 = Flow, 1 = Return
Return: Automatic detection function for heat output inactive. Max. possible partial heat load when D.000 is on Auto.
D.018Pump operating mode1 = Comfort (continuously operating pump)
Internal pump is switched on when the heating flow tem- perature is not at Heating off and the heat requirement is enabled via an external control
3 = Eco (intermittently operating pump)
Internal pump is switched on every 25 minutes for 5 minutes once the overrun time has elapsed
3 = Eco
D.019Pump operating mode: 2-stage pumpSetting for two-stage pump operating mode
0: Burner mode stage 2, pump prerun/overrun stage 1
1: Heating mode and pump prerun/overrun stage 1, domestic hot water mode stage 2
2: Automatic heating mode, pump prerun/overrun stage 1, domestic hot water mode stage 2
3: Always stage 2
4: Automatic heating mode, pump prerun/overrun stage 1, domestic hot water mode stage 1
2
D.020Max. DHW temperature target valueAdjustment range: 50–70 °C (actoSTOR 65 °C)65 °C
D.022DHW demandOn, OffNot ad- justable
D.023Heating mode statusHeating on, heating off (summer mode)Not ad- justable
D.025Ext. eBUS signal: Cylinder char- gingOn, OffNot ad- justable
D.026Auxiliary relay1 = Circulation pump
2 = External pump
3 = Cylinder charging pump
4 = Extraction hood
5 = External solenoid valve
6 = External fault message
7 = Solar pump (not active)
8 = eBUS remote control (not active) 9 = Anti-legionella pump (not active) 10 = Solar valve (not active)
2 = External pump
D.027Accessory relay 1Switching of relay 1 on the VR 40 "2 in 7" multi-func- tional module
1 = Circulation pump
2 = External pump
3 = Cylinder charging pump
4 = Extraction hood
5 = External solenoid valve
6 = External fault message
7 = Solar pump (not active)
8 = eBUS remote control (not active) 9 = Anti-legionella pump (not active) 10 = Solar valve (not active)
2 = External pump
D.028Accessory relay 2Switching of relay 2 on the VR 40 "2 in 7" multi-func- tional module
1 = Circulation pump
2 = External pump
3 = Cylinder charging pump
4 = Extraction hood
5 = External solenoid valve
6 = External fault message
7 = Solar pump (not active)
8 = eBUS remote control (not active) 9 = Anti-legionella pump (not active) 10 = Solar valve (not active)
2 = External pump
D.029Water circulation vol. actual value
Actual value in m3/hNot ad- justable
D.033Fan speed target value
In rpmNot ad- justable
D.034Fan speed actual valueIn rpmNot ad- justable
D.0353-way valve position
Heating mode
Parallel operation (mid-position) DHW mode
Not ad- justable
D.036DHW flow rateIn l/minNot ad- justable
D.039Solar inlet temp. actual valueActual value in °CNot ad- justable
D.040Flow temperature actual valueActual value in °CNot ad- justable
D.041Return temperature actual valueActual value in °CNot ad- justable
D.044Ionisation value actual valueDisplay field 0 to 1020
> 800 no flame
< 400 good flame
Not ad- justable
D.046Pump mode0 = Relay with disable facility 1 = PWM with disable facility
0 = Relay with disable facility
D.047Current outside temperature(with Vaillant weather-compensated control) Actual value in °CNot ad- justable
D.050Offset min. speedIn rpm, adjustment range: 0 to 3000Nominal value set in factory
D.051Offset max. speedIn rpm, adjustment range: -990 to 0Nominal value set in factory
D.058Solar post-heating0 = Solar post-heating deactivated
3 = DHW activation target value minimum 60 °C, thermo- static mixing valve required between product and draw- off point
0 = Solar post-heating deactivated
D.060Number of safety therm. shut- downs
Number of shutdowns
Not ad- justable
D.061No. of shut-downs in ign. flame controller
Number of unsuccessful ignitions in the last attemptNot ad- justable
D.064Avg. ignition time
In secondsNot ad- justable
D.065Max. ignition timeIn secondsNot ad- justable
D.067Remaining anti-cycl. time for heat- ingIn minutesNot ad- justable
D.068Number of first start attemptsNumber of unsuccessful ignitionsNot ad- justable
D.069Number of second start attemptsNumber of unsuccessful ignitionsNot ad- justable
D.0703-way valve operation0 = Normal operating mode
1 = Parallel operation (mid-position)
2 = Permanent heating position
0 = Normal operating mode
D.071Max. heating target flow temp.
40 to 80 °C75 °C
D.072Pump overrun after cylinder char- gingAdjustable from 0–10 minutes in increments of 1 minute
2 mins
D.073Offset setting for comfort modeAdjustable from-15Kto5K0
D.074Anti-legionella funct. with integ- rated cyl.0 = Off
1 = On
1 = On
D.075Max. cylinder charging time20–90 min45 mins
D.076Device Specific NumberDevice specific number = DSN
1 = VU 126/5-5 (H-GB) ecoTEC plus 612
3 = VU 156/5-5 (H-GB) ecoTEC plus 615
4 = VU 186/5-5 (H-GB) ecoTEC plus 618, VU 186/5-5 (P-GB) ecoTEC plus 618
9 = VU 246/5-5 (H-GB) ecoTEC plus 624
14 = VU 306/5-5 (H-GB) ecoTEC plus 630, VU 306/5-5 (P-GB) ecoTEC plus 630
20 = VU 386/5-5 (H-GB) ecoTEC plus 637 6 = VUW 196/5-5 (H-GB) ecoTEC plus 825
10 = VUW 246/5-5 (H-GB) ecoTEC plus 832, VUW 246/5-5 (P-GB) ecoTEC plus 832
62 = VUW 306/5-5 (H-GB) ecoTEC plus 835
17 = VUW 286/5-5 (H-GB) ecoTEC plus 838, VUI 286/5- 5 (H-GB) ecoTEC plus 938
Not ad- justable
D.077DHW partial loadAdjustable cylinder charging output in kW
D.078DHW max. flow temperatureLimit on cylinder charging temperature in °C 50 °C – 80 °C
Note
The chosen value must be at least 15 K or 15 °C above the target cylinder value.
75 °C
D.080Heating operating hoursIn hours (h)Not ad- justable
D.081DHW operating hoursIn hours (h)Not ad- justable
D.082Heating burner startsNumber of burner start-upsNot ad- justable
D.083DHW burner startsNumber of burner start-upsNot ad- justable
D.084Maintenance inAdjustment range: 0 to 3000 hrs and "---" for deactivated„---”
D.088Min. DHW flow rateSwitch-on delay for domestic hot water draw-off detec- tion via impeller (only products with integrated domestic hot water generation)
0 = 1.5 l/min and no delay,
1 = 3.7 l/min and 2 sec. delay
1.5 l/min and no delay
D.090eBUS controllerStatus of digital control Recognised, not recognisedNot ad- justable
D.091DCF77 Status with connected external proble with DCF77 receiver0 = no reception
1 = reception
2 = synchronised
3 = valid
Not ad- justable
D.092actoSTOR communication statusactoSTOR module detection
0 = Not connected
1 = Connection fault: No communication via PeBus, actoSTOR module was previously detected
2 = Connection active
Not ad- justable
D.093Adjust Device Specific Number
Device Specific Number (DSN) Adjustment range: 0 to 99
D.094Clear fault historyDelete fault list
0 = No
1 = Yes
D.095Software version: PeBUS parti- cipantPCB (BMU) Display (AI) actoSTOR (APC) HBI/VR34Not ad- justable
D.096Reset to factory settings?
Reset all adjustable parameters to factory setting 0 = No
1 = Yes
D.097Activation of the second diagnostic levelPassword:17Password:17
D.098Coding resistorDisplay xx.yy
xx = Coding resistor 1 in cable harness for output range:
8 = VU 126/5-5 (H-GB) ecoTEC plus 612; VU 156/5-5 (H-GB) ecoTEC plus 615; VU 186/5-5 (H-GB) ecoTEC plus 618, VU 186/5-5 (P-GB) ecoTEC plus 618; VUW 196/5-5 (H-GB) ecoTEC plus 825
9 = VU 246/5-5 (H-GB) ecoTEC plus 624; VUW 246/5-5 (H-GB) ecoTEC plus 832; VUW 246/5-5 (P-GB) ecoTEC plus 832
10 = VU 306/5-5 (H-GB) ecoTEC plus 630; VU 306/5-5 (P-GB) ecoTEC plus 630; VUW 306/5-5 (H-GB) ecoTEC plus 835
11 = VU 386/5-5 (H-GB) ecoTEC plus 637; VUW 286/5- 5 (H-GB) ecoTEC plus 838; VUI 286/5-5 (H-GB) ecoTEC plus 938
yy = Coding resistor 2 on PCB for gas group: 02 = P gas
03 = H gas
07 = L gas
Not ad- justable

vaillant diagnostic table

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