Expansion Vessel for Thematek Boiler F 24 E - Ref. 0020057805
If you notice that the pressure of your boiler fluctuates sharply and the safety valve is leaking, you may need the expansion vessel for the Thematek F 24 E - Ref. 0020057805. This part absorbs the increase in water volume when heated, thus preventing pressure issues in the system. It is compatible with models such as ThemaClassic C 24 E, ThemaClassic F 24 E, and SemiaTek C 24, among others. It is recommended to replace it when it shows a loss of charge or if the membrane is broken.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 0020057805
Expansion vessel with reference 0020057805. Eight confirmed compatibilities: ThemaClassic C 24 E and ThemaClassic C 25 E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval ThemaClassic C 24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 25 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic F 24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic F 25 E | ThemaClassic | Contrasted |
| Saunier Duval Thematek C 24 E | Thematek | Contrasted |
| Saunier Duval Thematek F 24 E | Thematek | Contrasted |
| Saunier Duval SemiaTek C 24 | SemiaTek | Contrasted |
| Saunier Duval SemiaTek F 24 | SemiaTek | 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 ref. 0020057805 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.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 0020057805. If it is not visible, do not identify the part from its shape alone.
- Check the full boiler model on its data plate and look for it in the model associations on this page.
- Compare the connections and physical body with the original part before installation.
- If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Symptoms and faults that the expansion vessel 0020057805 resolves.
The expansion vessel absorbs the expansion of water when heated. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
Every so often, the circuit needs to be refilled because the pressure does not hold.
Cause: The airless vessel no longer absorbs the extra volume of water when heated, so the system loses pressure with use.
First, rule out a visible leak in the tank itself, in the filling valve, or in the radiators.
- 02
The safety valve drips, especially when the boiler has been providing heating for a while.
Cause: Without available expansion margin, the pressure reaches the gas valve opening point sooner.
Check if the dripping occurs in every heating cycle or if it is occasional; the former indicates more clearly towards the expansion vessel.
- 03
The expansion vessel does not bounce when pressed with the hand; it feels rigid and without air.
Cause: When the membrane breaks or the precharge is lost, the vessel stops having that characteristic elasticity.
Press the casing with the cold boiler and the circuit depressurized: if nothing gives, that's the clue.
- 04
The pressure gauge spikes as soon as the heating is turned on, more than you remember from before.
Cause: It is the typical signal of a vessel that no longer compensates for the expansion of hot water.
Compare the cold pressure with that of the first few minutes of operation to confirm the jump.
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.
Expansion vessel data Saunier Duval 0020057805
- Catalogue reference
- 0020057805
- Brand
- Saunier Duval
- Type of part
- Expansion vessels
- Units in stock
- 1 unit
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- Return
- 14 days
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval Thematek C 24 E Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the expansion vessel 0020057805
Does this expansion vessel Ref. 0020057805 fit a Thematek F 24 E?
What fault does replacing the expansion vessel of the Semia Tek F 24 resolve?
Spare parts related to Saunier Duval ThemaClassic
