Domusa Avanttia NG floor-standing condensing boiler on a white background
Inside the Domusa Avanttia NG: burner, expansion vessel, circulator and DHW tank
Domusa Avanttia NG installed against a wall in a home
Single-coil stainless steel boiler body of the Avanttia NG
Low-NOx premix burner of the Domusa Avanttia NG boiler

Domusa Avanttia NG floor-standing gas condensing boiler with stainless DHW tank

Model
Regular price€3.143,04
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  • 2 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.

Floor-standing gas condensing boiler with a stainless DHW tank for homes, from 24 to 33 kW

The Domusa Avanttia NG is a floor-standing gas condensing boiler with a stainless steel hot water tank inside the same casing. Q-Tech assembles and tests it in our workshop as part of a pre-assembled plant room, or integrates it into your existing plant room.

Summary

Type Floor-standing gas condensing boiler with built-in domestic hot water (DHW) tank
Brand and model Domusa Teknik Avanttia NG, 4 models: 24 HDX 120 L, 24 HDX 150 L, 28 HDX 150 L and 33 HDX 150 L
Use Heating and domestic hot water (DHW)
Useful output at 50/30 °C From 25.3 to 35.6 kW depending on model
Hot water Stainless tank of 120 or 150 litres; from 826 to 957 litres per hour continuous with a 30 °C rise
Efficiency Class A for heating and DHW, XL DHW profile; 1:10 modulation; NOx class 6
Fuel Natural gas from the factory; propane after adjustment by a technician authorised by Domusa
Warranty 3 years from official commissioning, extendable to 7 years with the Domusa Teknik extension
Q-Tech installation Inside a pre-assembled plant room or on-site by an Expert Technician

What is the Domusa Avanttia NG?

The Domusa Teknik Avanttia NG is a floor-standing gas condensing boiler for heating and DHW with a built-in stainless steel tank of 120 or 150 litres. Its premix burner adjusts combustion through flame ionisation and modulates from 1 to 10. It has a footprint of 560 × 610 mm.

What problem does it solve?

In a home with several bathrooms, an instantaneous combi boiler falls short when two taps run at the same time. A separate cylinder solves the flow rate, but it takes up space and adds connections and failure points to the plant room.

The Avanttia NG combines boiler and stainless tank of 120 or 150 litres in a single unit. Domusa states up to 367 litres in 10 minutes with a 30 °C rise and an XL DHW profile. Q-Tech calculates the heating and hot water demand before recommending a model.

Technical data

Boiler type Floor-standing, condensing, with DHW tank
Fuel Natural gas (G20) set at the factory; propane (G31) by changing the gas parameter and adjusting combustion
Gas supply pressure 20 mbar with natural gas; 37 mbar with propane
Efficiency Over 108% on net calorific value at 30% load, according to Domusa
Seasonal space heating efficiency 92% (class A)
Modulation 1:10
NOx emissions Class 6, below 56 mg/kWh under the 2018 ErP regulation
Boiler body Single-coil stainless steel, with no parallel circuits or welds
Combustion control Gas Adaptative, with flame ionisation control
DHW tank Stainless steel, 120 or 150 litres, with recirculation connection
Heating temperature From 25 to 80 °C
DHW temperature From 10 to 65 °C
Heating pressure From 0.5 to 3 bar
Power supply 230 V
Protection rating IP20
Flue Concentric Ø 60/100 or 80/125 and twin-pipe Ø 80/80
Equipment High-efficiency circulator, diverter valve, by-pass, heating and DHW expansion vessels, safety valves, automatic air vent, filling valve, dielectric unions and condensate trap
Made in Spain

Models and data by variant

Model Useful output 80/60 °C Useful output 50/30 °C Continuous DHW (30 °C rise) DHW in 10 minutes Tank Expansion vessel Height Empty weight Domusa reference
24 HDX 120 L 23.7 kW 25.3 kW 826 l per hour 304 l 120 l 8 l 1,555 mm 170 kg TAVA000164
24 HDX 150 L 23.7 kW 25.3 kW 892 l per hour 357 l 150 l 8 l 1,725 mm 180 kg TAVA000165
28 HDX 150 L 28 kW 30.1 kW 957 l per hour 367 l 150 l 12 l 1,725 mm 180 kg TAVA000166
33 HDX 150 L 33 kW 35.6 kW 957 l per hour 367 l 150 l 12 l 1,725 mm 180 kg TAVA000167

Width and depth: 560 × 610 mm on all four models. Data from the Domusa Teknik 2026 price list and Avanttia NG catalogue; empty weight from the installation manual.

Compatibility and limits

  • It leaves the factory set for natural gas. For propane, a professional authorised by Domusa Teknik changes the gas parameter and adjusts combustion.
  • Flue with Domusa accessories only: concentric Ø 60/100 up to 10 m horizontal and 11 m vertical; concentric Ø 80/125 up to 20 and 22 m; twin-pipe Ø 80/80 up to 30 m. Each bend reduces the allowed length.
  • The hydraulic connections are routed to the left, right or top with the Avanttia NG outlet kit, sold separately.
  • It accepts a room thermostat, an OpenTherm remote control such as the Lago FB OT+ and an outdoor sensor to adapt the output to the weather.
  • Domusa includes commissioning by its official technical service; travel is charged separately.
  • Gas and heating installation and certification require a licensed installation company.

When this product is not the right choice

  • If you want to move away from gas and keep your radiators, the Domusa Dual Clima HT Pro heat pump delivers flow temperatures of up to 75 °C.
  • If you want heating and hot water from an indoor unit without combustion, the Domusa NanoClima 4 HDX 135 has 135 litres of DHW.
  • If the home has neither natural gas nor a propane tank, the boiler has no fuel: choose a heat pump.
  • If you only need heating, without hot water storage, a boiler without a tank takes up less space.

Frequently asked questions

Which model do I need?

It depends on the heating output and the hot water use. Send us the floor area, insulation, emitters and number of bathrooms on WhatsApp and we will recommend a model.

Does it work with propane?

Yes. It leaves the factory set for natural gas, and a technician authorised by Domusa converts it to propane by changing a parameter and adjusting combustion.

Is it hydrogen ready?

Domusa Teknik does not publish compatibility with hydrogen blends for the Avanttia NG. Its approved gases are natural gas and propane.

What warranty does it have?

Three years from official commissioning, according to Domusa Teknik, with an annual service. It extends to 7 years, including travel, labour and spare parts, if you take out the extension with the Domusa technical service within one month of commissioning.

What is the lead time?

It is in stock at our warehouse. Because of its weight, transport is quoted separately.

Can I install it myself?

No. It needs a licensed installation company and Domusa commissioning; Q-Tech integrates it and carries out the pre-commissioning check.

Q-Tech installation and support

The Avanttia NG can arrive on site inside a pre-assembled plant room: Q-Tech assembles it in our workshop with the rest of the plant room, configures it and runs safety, operating and pressure tests. The plant room arrives tested and ready to connect; the final connection is made by the site installer or by Q-Tech with the on-site Expert Technician by the day. See the process in Pre-Montaje Avanzado and in the Expert Technician workshop pre-assembly service.

If another company installs the boiler, or it replaces a boiler in an existing system, Q-Tech first carries out a verification visit with the on-site hourly Expert Technician. The pre-commissioning check leaves everything ready for the official commissioning by the Domusa technical service.

To choose a model, book a technical call or message us on WhatsApp. More units and components in heating.

Q-Tech VDI 2035 calculator

Check whether the water in your heating system meets the VDI 2035 guideline (Part 1, 2021). Enter the output, the system volume in litres and the hardness and conductivity of your mains water: the calculator gives you the verdict and the three key figures for filling or topping up the circuit. If you need it, we will send you the full report.

Guidance only: check the manufacturer's requirements.

VDI 2035 calculator: check whether your system water meets the guideline. Open the calculator

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. Because of its weight, transport is quoted separately.

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