
Combustion Chamber + Heat Exchanger Vaillant VMW 226/3-3 (Giannoni GM30-45-004-09) Ref. GM30-45-004-09
Refurbished combustion chamber assembly with primary condensing heat exchanger for Vaillant ecoTEC pro VMW 226/3-3. Manufactured by Giannoni (GM30-45-004-09) and equivalent to OEM Vaillant 0020135129 (replaces 0020018181). Its function is to transfer heat and condense the flue gases, affecting the start-up, efficiency, and safety of the equipment.
VAT included
Consult via WhatsAppVaillant boilers compatible with reference GM30-45-004-09
Combustion chambers with reference GM30-45-004-09. A proven compatibility: VMW 226/3-3.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Vaillant VMW 226/3-3 | ecoTEC pro | Contrasted |
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 reference GM30-45-004-09 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.
Symptoms and faults that the GM30-45-004-09 combustion chambers solve.
Common symptoms and faults
- 01
Intermittent lockouts F.28/F.29 after several attempts
Cause: Recirculation of gases or condensate in the chamber due to obstruction in the passages of the heat exchanger or siphon.
Inspect siphon/drain; check flue/air intake; observe moisture/frost inside chamber; measure flame stability.
- 02
F.25 with correct ventilation and flue.
Cause: Smoke side passages of the heat exchanger dirty/deformed
Measure flue gas temperature; check back pressure; visual inspection of the bundle; assess chemical/mechanical cleaning.
- 03
F.20/F.23 with a very high ΔT supply/return
Cause: Hydraulic blockage of the primary circuit due to sludge/incrustation
Check the pump flow and filters; perform flushing/cleaning; if the abnormal ΔT persists, primary defective.
- 04
Condensate dripping/trace on the chamber base
Cause: Internal leak of the heat exchanger to the combustion chamber
Hydraulic tightness test of the primary with sealed points; presence of white deposits/oxides in the chamber.
- 05
Smell of combustion and marks on the sight glass
Cause: Recirculation through partially blocked flue passages
Check the integrity of the flange gasket, the condition of the burner, and the cleaning of the fins on the body.
Fault codes from Vaillant that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.28 | Start-up fault: ignition failed | Check gas valve/gas pressure, electrodes/ignition, and grounding. Also, inspect the intake pipe and condensate drain for obstruction. Relationship: condensate in the chamber or blockage/re-circulation of flue gases within the body can prevent ignition and may require replacement if there is damage/corrosion in the assembly. |
| F.29 | Flame loss; failed ignition retry | In addition to gas and mass, check the exhaust/admission and condensate discharge. Relationship: accumulation of condensate in the chamber or recirculation due to blocked passages in the heat exchanger can extinguish the flame; if it persists after cleaning/adjustments, consider replacing the body. |
| F.25 | Combustion gas temperature too high | Check the gas flow (obstruction, wind), internal bleeding, flow rate, and fan. Relationship: dirty/deformed fins/passages of the heat exchanger raise the flue gas temperature; if cleaning does not restore values, the heat exchanger may be damaged. |
| F.20 | Disconnection due to temperature limiter (STB) | Check NTC, bleeding and flow rate. Relationship: internal blockage of the primary (sludge/incrustation) reduces flow rate, triggers STB; if the flushing/hydraulic cleaning does not resolve, replace the primary. |
| F.23 | Excessive temperature differential; insufficient flow | Check the pump, air in the circuit, hydraulic filter, pressure sensor. Relationship: hydraulic throttling within the heat exchanger increases ΔT supply/return; rule out with cleaning and, if it persists, replace the body. |
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 combustion chambers Vaillant GM30-45-004-09
- Catalogue reference
- GM30-45-004-09
- Brand
- Vaillant
- Type of part
- Combustion chambers
- 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.
- Type of part
- Combustion chamber with primary condensing heat exchanger
- Boiler brand
- Vaillant ecoTEC pro VMW 226/3-3
- Component manufacturer
- Giannoni
- Component model
- GM30-45-004-09
- equivalent OEM Vaillant
- 0020135129 (replaces 0020018181)
- Primary material
- Stainless steel
- Key functions
- Primary heat exchanger, sealed combustion chamber, condensation, and condensate drainage.
- Cut off gas and electrical supply before intervening.
- Wait for complete cooling; risk of burns.
- Mandatory bleeding of the circuit (program P.0) after any opening.
- Use new single-use gaskets in the flange/chamber and seals resistant to condensates.
- Check the gas tightness and the flue gas circuit after installation.
- Check and, if necessary, adjust combustion (CO₂) according to the manual.
- Torque: apply the one specified by Vaillant in the model's manual.
- Check the free drainage of the condensate siphon after the intervention.












