Control PCB (BMU) Vaillant ecoTEC Plus 3-5 (NEC TL-AC PM-02) Ref. 0020035420
Main PCB (BMU) for Vaillant ecoTEC plus /3-5. Manages ignition, flame control, pumps, sensors, and communication. Valid for confirmed Spanish models: VMW ES 346/3-5, VMW 296/3-5 R3, and VM 376/3-5 with references 0020035420/0020092478. Refurbished unit, requires verification and parameterization.
VAT included
Consult via WhatsAppVaillant boilers compatible with reference 0020035420
PCB with reference 0020035420. Three confirmed compatibilities from two independent sources: VMW ES 346/3-5 and VMW 296/3-5 R3.
Compatibility confirmed
| Boiler model | Family | Verification |
|---|---|---|
| Vaillant VMW ES 346/3-5 | ecoTEC plus (VMW, mixed) 3-5 | Confirmed · 2 sources |
| Vaillant VMW 296/3-5 R3 | ecoTEC plus (VMW, mixed) 3-5 | Confirmed · 2 sources |
| Vaillant VM 376/3-5 | ecoTEC plus (VM, heating only) 3-5 | Confirmed · 2 sources |
Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.
How to check if the ref. 0020035420 is the part for your boiler
What determines it is not the boiler model, but the reference printed on the part you already have installed.
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Symptoms and faults that the PCB 0020035420 resolves.
The PCB controls the ignition, modulation, and safety features of the boiler. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler does not start and shows F.63 or F.70 after changing the PCB or the display.
Cause: Damaged EEPROM or unconfigured DSN
Try resetting; enter d.93 to program the DSN; if F.63 persists, the BMU is faulty.
- 02
F.64/F.65 intermittent, spontaneous shutdowns
Cause: Overheated electronics or internal fault
Check location/temperature, network voltages and ground; if correct, replace BMU.
- 03
Repeated F.28/F.29 with gas and electrodes checked.
Cause: Ignition/ionization stage on faulty PCB
Measure spark and ionization current; if there is instability with all the correct peripherals, the BMU fails.
- 04
F.61/F.62 associated with the gas valve without apparent cause
Cause: Defective relay or output of the BMU
Check the packs and valve; if the activation is erratic from the PCB, replace the BMU.
- 05
Incoherent NTC readings or F.72 with new NTC.
Cause: Damaged analog inputs of the BMU
Check the continuity of harnesses and NTC resistance values; if they remain inconsistent, the BMU is defective.
Fault codes from Vaillant that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.63 | EEPROM fault | Replace the PCB if the fault persists after reset. Direct relationship with the BMU memory. |
| F.64 | Electronic fault/sensor | Check the NTC supply/return, harnesses, and ionization electrode. If the signals and wiring are correct, the BMU may be faulty. |
| F.65 | Electronic temperature too high | Check location/ventilation and, if it persists, replace the PCB. Indicates overheating or damaged electronics. |
| F.67 | Electronics/call: implausible signal | Check the igniters, flame guards, and electrodes. If there are no mechanical anomalies, there is likely a fault in the flame control stage of the BMU. |
| F.70 | Invalid appliance code (DSN) | After changing the screen/BMU, adjust the device identification in d.93 and check the coding resistance. Without this, the boiler does not start. |
| F.28 | Ignition fault | Discard gas, electrodes, transformer, and ground connection. If everything is fine, the ignition stage in the BMU may be damaged. |
| F.29 | Operating fault: failed ignition | Check the flue gas recirculation, condensate, grounding, and wiring to the valve/electrode. Persistence with everything correct points to BMU. |
| F.61/F.62 | Gas valve delayed activation/disconnection fault | Check the actuator to the valve and the valve itself. If there is erratic activation with the wiring okay, suspect the relays/power stage of the BMU. |
| F.72 | Fault sensor supply/return (excessive difference) | Check the NTC and its thermal coupling. If readings are erratic with good NTCs, there may be a fault in the analog inputs of the BMU. |
These symptoms can have more than one cause. If your boiler displays a fault code, send it to us via WhatsApp along with a photo of the labeling, and we'll tell you if this is the part.
Data sheet for the Vaillant PCB 0020035420
- OEM reference
- 0020035420
- Brand
- Vaillant
- Type of part
- PCBs (control boards)
- Units in stock
- 1 unit
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- Return
- 14 days
Data read on the part and in the manufacturer's documentation
What we have not been able to verify does not appear here.
- OEM reference Vaillant
- 0020035420 (replaced by 0020092478; possibly 0020092421)
- Compatible family (ES)
- ecoTEC plus /3-5: VMW ES 346/3-5, VMW 296/3-5 R3, VM 376/3-5
- Power supply
- 230 V~ 50 Hz
- Function
- BMU: ignition control, flame, sensors, fan, pump, and eBUS
- Post-change parameterization
- Adjustment of DSN in d.93 and verification of coding resistance
- Status
- Refurbished and tested on the bench
- Cut off the electrical supply and close the gas before intervening.
- Static discharge; ESD handling of the PCB.
- Do not bypass protections. Check the grounding of the appliance.
- After the change, parameterize d.93 (DSN) and check the coding resistance.
- Run test programs and combustion/safety checks according to the manual.
- Do not reuse gas seals if gas train components are disassembled.
- Check the tightness and bleed the installation according to the Vaillant procedure.
Frequently asked questions about the PCB 0020035420
Is it compatible with my ecoTEC plus VMW ES 346/3-5?
What should I do if F.70 appears after installing the PCB?
I have F.28/F.29: is it always the PCB?
Should I reconfigure parameters after changing the BMU?
Is it valid for VM 376/3-5 (heating only)?
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