Chamber + Heat exchanger Vaillant VMW 346/5-5 (Giannoni GM30-45-008-10) Ref. GM30-45-008-10
Combustion chamber assembly with primary condensing heat exchanger for Vaillant ecoTEC plus 30–34 kW (e.g., VMW ES 346/5‑5). Giannoni core GM30‑45‑008‑10. Its function is to transfer heat from the burner to the water circuit and condense the flue gases, which is key for the performance and thermal safety of the boiler.
VAT included
Consult via WhatsAppVaillant boilers compatible with reference GM30-45-008-10
Combustion chambers with reference GM30-45-008-10. Four confirmed compatibilities: VMW ES 346/5-5 (R4/R5) and VM ES 306/5-5 (equivalent to VU 306/5-5).
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Vaillant VMW ES 346/5-5 (R4/R5) | ecoTEC plus (combi) | Contrasted |
| Vaillant VM ES 306/5-5 (equivalent VU 306/5-5) | ecoTEC plus (heating only) | Contrasted |
| Vaillant VSC 306/2-C 200 | ecoCOMPACT | Contrasted |
| Vaillant VK 306 | ecoVIT plus (floor, heating only) | 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 GM30-45-008-10 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 GM30-45-008-10 combustion chambers solve.
Common symptoms and faults
- 01
Stops due to overheating after a few minutes of demand
Cause: Primary heat exchanger partially obstructed by scale/sludge
Check the ΔT supply/return (>35 K) and rapid gradient; inspect the filter/return and the core if the rest is correct.
- 02
Boiling/cavitation noise on startup
Cause: Hot spots due to poor thermal transfer in the primary.
Check bleeding P.0, service pressure, and presence of sludge; if it persists, consider descaling or replacement of the core.
- 03
Condensate drain leak with iron smell/trace
Cause: Internal leak of the heat exchanger to the condensation chamber
Visual inspection of the base and collector joints; hydraulic tightness test of the core outside the boiler.
- 04
Recurring fault codes F.23/F.24 even after cleaning the installation.
Cause: Reduced useful section in water channels of the heat exchanger
Measure temperature drop and check pump flow; if normal, the problem is with the heat exchanger.
Fault codes from Vaillant that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.20 | Safety disconnection due to temperature limiter (STB) | Overheating due to poor heat transfer or obstruction in the heat exchanger. Check bleeding, NTC, circulation, and condition of the core; replace if there is scaling/blocked sections. |
| F.22 | Lack of water / insufficient pressure | It can occur if there is a micro-leak in the heat exchanger or after bleeding. Reset the pressure, bleed, and check the tightness of the primary; rule out internal leakage of the core. |
| F.23 | Excessive temperature variation between supply and return | Typical of reduced flow in the primary or insufficient flow rate. Check the pump/filter and, if it persists with a clean installation, check the thermal drop of the heat exchanger and replace it if it is clogged. |
| F.24 | Too rapid temperature increase (insufficient circulation) | If the pump and the installation are correct, a partially blocked primary accelerates the temperature rise. Measure the gradient and ΔT; replace the core if the restriction is confirmed. |
| F.25 | Combustion gas temperature too high | Poor transfer or obstructed fins/smoke can raise the flue gas temperature. Check the flue gas path and clean the body; if the problem is with the core, replace it. |
| F.28/F.29 | Ignition failure / flame loss in service | These are not typical faults of the primary system, but a siphon/condensate blockage in the combustion chamber or condensate return can contribute. Check the condensate drainage and the tightness of the chamber before ruling out the heat exchanger. |
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 GM30-45-008-10
- Catalogue reference
- GM30-45-008-10
- 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.
- manufacturer_component
- Giannoni
- marked_on_board
- GM30-45-008-10
- type
- Combustion chamber with primary condensing heat exchanger
- vaillant_application
- ecoTEC plus 30–34 kW (e.g., VMW ES 346/5‑5; VM ES 306/5‑5; ecoCOMPACT VSC 306; ecoVIT VK 306) according to series
- refs_vaillant_equivalents
- 0020135133 (replaces 0020018183) / 0020209546 (according to series and supply of sensors)
- state
- Refurbished (cleaning, leak testing, and heat exchanger surface inspection)
- Cut off gas and electrical supply before intervening.
- Empty the primary circuit and then bleed (program P.0) until all the air is removed.
- Always use new gaskets and screws when assembling the heat exchanger (the gaskets are single-use).
- Check combustion and CO₂ with analyzer after the change; adjust if necessary according to the manual.
- Check and clean the siphon/condensate drain to prevent returns to the chamber.
- Respect the torque specifications indicated by the manufacturer on flanges/collectors (consult the installation manual for the specific model).
- Confirm if your series requires a version with/without associated sensor (different OEM references).
Frequently asked questions about the GM30-45-008-10 combustion chambers.
Is it compatible with my Vaillant ecoTEC plus VMW ES 346/5‑5?
What faults is this heat exchanger involved in?
Do I need the version with a sensor?
What else should I change when replacing it?
