Expansion Vessel Saunier Duval Isofast F 30 EA Ref. S1025200
Refurbished Saunier Duval Expansion vessels

Expansion Vessel Saunier Duval Isofast F 30 EA Ref. S1025200

Saunier Duval presents the Isofast F 30 EA expansion vessel, a component that absorbs the increase in water volume when heated. When this component fails, you may notice that the boiler pressure fluctuates sharply, and the safety valve may start to leak. This expansion vessel is compatible with several models in the Isofast range, such as the Isofast F 30 E and the Isofast F 35 E H-MOD, among others. A technician should confirm through diagnosis whether it needs to be replaced when you observe these symptoms to avoid further issues in the system.

Type of part
Expansion vessels
Status
Refurbished
Catalogue reference
S1025200
Warranty
1 year
VAT included Stock · 7 units
Compatibility

Saunier Duval boilers compatible with the reference S1025200

Expansion vessel with reference S1025200. Five confirmed compatibilities: Isofast F 30 EA and Isofast F 30 E.

Verified compatibility

Boiler modelFamilyVerification
Saunier Duval Isofast F 30 EASaunier DuvalVerified
Saunier Duval Isofast F 30 ESaunier DuvalVerified
Saunier Duval Isofast F 30 E H-MODSaunier DuvalVerified
Saunier Duval Isosplit F 30 E H-MODSaunier DuvalVerified
Saunier Duval Isofast F 35 E H-MODSaunier DuvalVerified

Can't see your model or have questions? The printed reference takes precedence. How to check it ·

Guide

How to check if the part S1025200 is the one for your boiler.

The part reference, model, and equipment revision must be verified against the manufacturer's documentation.

  1. Find the reference printed on the installed part and check whether it matches the catalogue reference S1025200. If it is not visible, do not identify the part from its shape alone.
  2. Check the full boiler model on its data plate and look for it in the model associations on this page.
  3. Compare the connections and physical body with the original part before installation.
  4. If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Diagnosis and fault codes

Symptoms that require diagnosis in the expansion vessel S1025200

The expansion vessel absorbs the expansion of water when heated. These are the typical symptoms and what to do:

Common symptoms and faults

  • 01

    The pressure suddenly rises as soon as the heating is turned on, even though it is correct when cold.

    Cause: This indicates that the internal membrane of the vessel has broken, preventing it from acting as an air cushion, and the circuit behaves as if it does not have a vessel.

    With the boiler cold, remove the cap from the Schrader valve of the expansion vessel and press the stem for a moment; if water comes out instead of air, the membrane is broken.

  • 02

    The circuit gradually loses pressure and needs to be refilled every few weeks.

    Cause: The vessel has lost nitrogen charge or has a leak, so it no longer compensates for the expansion of water when heated, and the system is short on pressure.

    Gently tap the glass on both halves with the boiler cold: if it sounds hollow evenly across the entire casing, it has lost the air precharge.

  • 03

    A knocking sound is heard in the pipes when opening the hot water or when starting the boiler.

    Cause: Without the air cushion in the expansion vessel to absorb the flow change, that pressure surge is transmitted throughout the entire system.

    Check for trapped air by bleeding the radiators before assuming it's the expansion vessel; the symptom is very similar.

  • 04

    The safety valve drips when the heating has been running for a while.

    Cause: Without the expansion vessel, the pressure in the circuit rises until the safety valve is forced to relieve it.

    Compare the cold pressure with the pressure after 15 minutes of operation: a strong and sustained increase indicates the expansion vessel, not the valve.

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.

Technical data

Expansion vessel data Saunier Duval S1025200

Catalogue reference
S1025200
Uniclima internal SKU
VEIF30EA
Brand
Saunier Duval
Type of part
Expansion vessels
Units in stock
7 units
Status
Refurbished
Warranty
1 year
Shipping
Delivery time shown at checkout
Return
14 days
Documentation

Manuals and technical documentation

Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.

Frequently asked questions

Frequently asked questions about the expansion vessel S1025200

Is this expansion vessel suitable for the Isofast F30 EA?
Yes, compatibility with Isofast F30 EA is confirmed, as well as with Isofast F 30 E, Isofast F 30 E H-MOD, and Isofast F 30 EH.
What fault does changing this expansion vessel resolve?
Correct frequent pressure drops, water hammer, or leaks from the safety valve when heating the water.

Spare parts related to Saunier Duval Saunier Duval

Delivery calculated by destination Delivery time shown at checkout
1-year warranty inspected and tested
14-day return uninstalled parts
Technical support we verify your model
Expansion Vessel Saunier Duval Isofast F 30 EA Ref. S1025200