ELIZ EURO 300 S21 | Vertical storage water heater

Product detailed description

Vertical storage water heaters are commonly used in residential and small commercial settings where space constraints require upright installation. This model is suitable for systems that need to combine multiple heat sources for water heating, such as boiler and solar. Installers working on central heating systems will find this heater appropriate for applications where hot water is required for domestic use and where electrical backup is needed. It is typically installed in mechanical rooms, basements or utility areas.

The ELIZ EURO 300 S21 is designed for floor mounting and is particularly useful in environments where vertical space is available and horizontal footprint is limited. It is intended for use in closed-loop systems with a maximum pressure of 8 bar and is compatible with a range of heating media including natural gas boilers, heat pumps and solar thermal collectors. The heater is not suitable for wall mounting and should be installed on a stable, level surface to ensure safe and efficient operation.

Technical parameters

type	EURO 300 S21
power	9000 (3x3000) W
voltage	400 V
protection	3x16 A
electrical protection	IP 24
water connection	3/4 inch
maximum tank pressure	8 bar
heating time from 12 to 65 °C	4.7 hours
heat exchanger connection	3/4 inch
heat exchanger surface area S1	1.33 m²
heat exchanger power S1	43 kW
heat exchanger surface area S2	1.07 m²
heat exchanger power S2	28 kW
wall mounting	no
safety cut-out	yes
weight	104 kg
product dimensions	670 x 1605 mm
tank warranty	5 years
product warranty	2 years
Code	ELZ_3359
Brand	ELIZ

The technical parameters are essential for correct sizing and system integration. The total power of 9000 W allows rapid heating when using the electric element. The heat exchanger surface areas (S1: 1.33 m², S2: 1.07 m²) determine the heat transfer efficiency and compatibility with external heat sources. The heater supports 3-phase 400 V supply and requires a 3×16 A circuit. The IP24 rating ensures protection against solid objects and splashing water, making it suitable for indoor installation. The heater is rated for a maximum operating pressure of 8 bar, which must be considered during system design and pressure regulation.

Installation and connection

Installation of the ELIZ EURO 300 S21 involves securing the unit on a flat, load-bearing surface. The heater has 3/4 inch threaded connections for both water and heat exchanger media. Before connecting, verify that the incoming water pressure does not exceed 8 bar and that the electrical supply matches the 3×16 A requirement. The heat exchanger inlets should be connected to the respective heat sources using compatible piping and valves. Ensure that the electrical supply is properly grounded and that the IP24-rated enclosure is intact. A safety cut-out is included for emergency shutdown. Common installation errors include incorrect orientation, failure to secure the unit firmly, and improper alignment of the heat exchanger connections. Always follow the manufacturer’s instructions for correct positioning and securement.

Compatibility and accessories

The heater is compatible with a variety of heat sources, including natural gas boilers, heat pumps and solar collectors. It can be integrated into systems with two distinct heating circuits, allowing simultaneous or sequential use of the heat exchangers. Additional components such as pressure relief valves, expansion vessels and temperature sensors may be required depending on the system configuration. No specific accessories are included with the heater. The unit is supplied with a metal safety valve and a wall bracket for support during installation. No related products are listed for this model.

Technical background for designers

The ELIZ EURO 300 S21 operates by transferring heat from two external sources via separate heat exchangers into the water stored in the insulated steel tank. The heat exchangers are made of steel and coated with zirconium glaze to resist corrosion and scale buildup. The electric heating element provides auxiliary heating when external sources are unavailable. The tank is also protected by two magnesium anodes, which significantly extend its service life by preventing internal corrosion. The heater integrates into closed-loop systems with a maximum pressure of 8 bar and requires a stable electrical supply for the electric element. The insulation is made of high-density polyurethane without CFCs, reducing heat loss and improving energy efficiency. The thermostat allows temperature adjustment between 7°C and 75°C, with an ECO mode that limits the maximum temperature to 55°C for reduced energy consumption. System efficiency is influenced by the condition of the heat exchangers, the quality of the insulation and the accuracy of the thermostat settings.

Service and operation

Maintenance of the ELIZ EURO 300 S21 includes periodic inspection of the anodes and heat exchangers for signs of corrosion or blockage. The electric element should be checked for proper operation and insulation integrity. The thermostat and safety cut-out should be tested regularly to ensure correct function. The heater does not require scheduled service intervals beyond routine visual checks. In case of unusual noise or reduced performance, the system should be inspected for leaks, blockages or electrical faults. The heater is equipped with a frost protection feature that prevents freezing damage by maintaining a minimum temperature setting. The manufacturer offers a 5-year warranty on the tank and a 2-year warranty on the overall product, covering defects in materials and workmanship.

Frequently asked questions

Can the heater be connected to both a boiler and a solar system simultaneously?
Yes, the heater has two separate heat exchangers that can be connected to two different heat sources, such as a boiler and a solar collector, enabling simultaneous or sequential use.

Is it possible to operate the heater using only the electric element?
Yes, the heater includes a 9000 W electric element that can be used independently of the heat exchangers for situations where external heat sources are not available or during peak demand.

What is the function of the ECO mode on the thermostat?
The ECO mode limits the maximum water temperature to 55°C to reduce energy consumption and minimize heat loss while still providing sufficient hot water for most domestic applications.

How does the frost protection feature work?
The heater’s thermostat is set to maintain a minimum temperature to prevent freezing in the tank and pipes, ensuring continued operation even in cold conditions.

Documents for download

• Technical documentation (PDF)