Ibaiondo SMF fixed-membrane solar expansion vessel without feet, front view
Ibaiondo solar range: SMF vessel without feet beside the SMR-P with feet and the vertical SMR

Ibaiondo SMF fixed-membrane expansion vessel for solar thermal systems

Capacity
Regular price€34,53
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  • 4 in stock
  • Backordered, shipping soon

At Q-TECH, we apply the same clear rules for everyone: the law protects you, and when applied correctly, it protects us as well. By processing your purchase, you accept our General Terms and Conditions of Sale. If you are purchasing as a consumer (B2C), nothing stated herein limits the rights granted to you by mandatory law (RDL 1/2007, TRLGDCU): the 3-year legal warranty of conformity and the right of withdrawal under the terms and with the exceptions legally provided, which are detailed below. References to "B2B" apply only to businesses and professionals.

Your guarantees

  • Rights intact: 14 days of withdrawal from receipt for most products—subject to the legal exceptions you will see below, such as goods made to your specifications—and a 3-year legal warranty of conformity, under the terms of the TRLGDCU.
  • Conformity with the description: we guarantee that the equipment will correspond to the published technical description and what one could reasonably expect from it (arts. 115 et seq. TRLGDCU). Images and videos are for guidance only: the manufacturer may supply a more recent revision of the product or introduce minor aesthetic, packaging, or firmware changes, without this constituting a lack of conformity as long as the described characteristics and performance are maintained.
  • Traceability that also protects you: we document the condition, serial number, and seal of each piece of equipment upon shipment, and we video-record the opening of returns; this is your proof of the condition in which the goods were delivered.

Responsible use and your part

  • If you are thinking of returning it, keep it as you received it: without installing or activating it, with its seals, accessories, and packaging intact. This is how to ensure a full refund, without deductions.
  • Handling that exceeds inspection reduces value: handling the equipment beyond what is necessary to verify its nature and operation may result in a real, assessed, and case-by-case justified deduction (art. 108.2 TRLGDCU), never a fixed percentage. In particular: activating or registering the serial number, linking it to a manufacturer's account or app, circulating water through hydraulic equipment, unsealing probes, or installing software or consumables. Initial inspection of the product does not lead to a deduction.
  • The same item must be returned: withdrawal requires returning the supplied unit. Different equipment, or equipment with prior use, age, or wear prior to purchase, does not constitute a valid withdrawal.
  • Installation and cybersecurity, shared responsibility: this is technical hardware; you are responsible for correct installation, credentials, patches, and backups, while we deliver a compliant product. Q-TECH is not liable for damages resulting from poor installation, incorrect configuration, or omission of patches by the customer or third parties (in B2C, without prejudice to the legal warranty and liability for intent or negligence, arts. 86 and 130 TRLGDCU).
  • Delivery of bulky goods: delivery is made to the curb. B2C: transport risk is ours until physical delivery (art. 66 ter); we recommend noting visible damages on the delivery note and notifying us of breakages within 24-48 hours with photographs to activate the insurance. B2B: inspection and notation on the delivery note are mandatory; hidden damages must be reported within 24 hours (art. 366 CCom). Unjustified rejection or incorrect shipping information will entail the actual outbound and return costs (approx. €85-550 for heavy machinery).

Made to your measure (Advanced Pre-Assembly)

  • If your order includes equipment, racks, hydraulic assemblies, or technical rooms made or configured according to your specifications (permanent joints, custom cuts or wiring, parameterization, pressure testing), these are custom goods without the right of withdrawal from the conclusion of the contract (art. 103.c TRLGDCU; CJEU Case C-529/19), which is informed before purchasing and documented in the signed Order Note. A test you request without permanent modification retains your right of withdrawal, with only the actual loss of value caused by that test being deducted. Would you prefer to receive it tested, configured, and ready to connect, without assuming these risks? Contract our Advanced Pre-Assembly or the prior technical audit.

If you are purchasing as a business or professional (B2B)

  • The transaction is governed by the Commercial Code: firm sale, without the right of withdrawal; notification of defects within 4 days (apparent) / 30 days (hidden), arts. 336 and 342. Q-TECH acts as a distributor and excludes indirect damages, loss of profit, and data loss, limited to the price of the equipment, without prejudice to the manufacturer's commercial warranty.

Product warnings v1.0 · June 2026. Information summary; the complete and binding conditions are those published at q-tech.es.

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Solar expansion vessel with a membrane that withstands 130 °C peaks for one hour

The Ibaiondo SMF expansion vessel absorbs the expansion of the fluid in your closed solar thermal circuit. Its membrane withstands peaks of 130 °C for one hour and accepts antifreeze up to 50%. At Q-Tech we fit it into your pre-assembled plant room, connected and tested with the rest of the solar circuit.

Summary

TypeFixed-membrane expansion vessel for solar thermal systems
Brand and modelIbaiondo SMF
UseClosed solar energy systems
Capacities8, 12, 18 and 24 litres
Maximum working pressure10 bar; 8 bar on the 24-litre model
Compatible withWater with antifreeze up to 50%
Factory pre-charge2.5 bar, with air
Manufacturer's warranty3 years
Q-Tech installationConnection and adjustment by an on-site hourly Expert Technician

What is the Ibaiondo SMF?

The Ibaiondo SMF is a fixed-membrane expansion vessel for closed solar energy systems that withstands peaks of 130 °C for one hour. A membrane separates the fluid from an air chamber. It is mounted without feet, on an R ¾" thread.

What problem does it solve?

The fluid in your solar circuit takes up more volume as it heats. Without an expansion vessel, pressure rises and fluid escapes through the safety valve. A solar circuit also sees temperature peaks, and Ibaiondo builds the SMF with a special membrane for those peaks.

A vessel designed for heating does not declare that resistance. Ibaiondo also recommends fitting a VI intermediate vessel, which dissipates heat before the expansion vessel. Its catalogue specifies it when the return can exceed 100 °C.

Technical data

ApplicationClosed solar energy systems
MembraneFixed, non-replaceable; withstands peaks of 130 °C for one hour
Body materialSteel
FinishWhite epoxy paint, RAL 9016
Factory pre-charge2.5 bar, with air; with inflation valve
Minimum temperature−10 °C
Maximum system temperature100 °C
AntifreezeUp to 50%
Water connectionR ¾" galvanised steel thread
Test pressure12 to 15 bar, depending on the maximum pressure
StandardsManufactured in accordance with the Pressure Equipment Directive 2014/68/EU
Made inSpain

Models and data by variant

ModelCapacityMaximum pressureDiameterHeightConnectionWeightReference
8 SMF8 litres10 bar200 mm340 mmR ¾"2.5 kg02008070
12 SMF12 litres10 bar270 mm310 mmR ¾"3.2 kg02012070
18 SMF18 litres10 bar270 mm415 mmR ¾"4 kg02018070
24 SMF24 litres8 bar320 mm430 mmR ¾"4.5 kg02024070

Compatibility and limits

  • The Ibaiondo SMF is intended for closed solar energy systems.
  • The maximum pressure is 10 bar, and 8 bar on the 24 SMF.
  • The factory pre-charge is 2.5 bar.
  • It accepts antifreeze mixtures up to 50%.
  • The membrane is fixed and cannot be replaced.
  • Ibaiondo recommends fitting a VI intermediate vessel as a heat dissipater.

When this product is not the right choice

ProductWhen to choose itMembraneMaximum pressureFactory pre-charge
Ibaiondo SMRYour solar circuit needs 35 to 200 litres or a replaceable membraneReplaceable; peaks of 130 °C for one hour10 bar2.5 bar
Ibaiondo CMFYour circuit is a closed heating or cooling circuitFixed4, 5 or 6 bar, depending on the model1.5 bar
Ibaiondo CMRYour circuit is domestic hot waterSuitable for drinking water10 bar; 8 bar on 24 litres3 bar

Frequently asked questions

Which Ibaiondo SMF model do I need?

It depends on the fluid volume, temperature and pressure of your solar circuit. With that data we help you choose in a technical call.

What is the delivery time?

It is in stock at our warehouse. If no units are left when you order, we order it urgently and tell you the updated delivery time.

Does it accept antifreeze?

Yes, up to 50%. Ibaiondo states that the SMF is suitable for antifreeze mixtures up to that proportion.

Can the membrane be replaced?

No. The Ibaiondo SMF membrane is fixed. With a replaceable membrane Ibaiondo makes the SMR solar expansion vessel, from 35 litres.

Do I need an intermediate vessel?

Ibaiondo recommends it. The VI intermediate vessel dissipates heat before the expansion vessel and protects its membrane.

How does it differ from the Ibaiondo CMF?

In membrane and pressure. The SMF withstands 130 °C peaks and works up to 10 bar; the CMF expansion vessel is for heating and cooling.

Q-Tech installation and support

The expansion vessel works with the pump station and safety valve of your solar circuit, and its air pressure is set to suit your installation. Q-Tech delivers it inside a pre-assembled plant room: assembled, wired and tested in our workshop, arriving on site ready to connect. You book it with the Técnico Experto workshop pre-assembly service.

If your installation already exists, an on-site hourly Expert Technician connects the Ibaiondo SMF and checks its pressure. You can see the full range in Ibaiondo expansion vessels or write to us on WhatsApp or from contact.

Documentation

Availability and lead times: this item is in stock at our warehouse. Occasionally, depending on the time of year, the stock update may contain an error. If no units are available when you place your order, we will order it urgently and inform you immediately of the updated delivery time.

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