ATTACK AS 1500 Buffer Tank with One Heat Exchanger (insulation included)

Product detailed description

ATTACK Buffer Storage Tank AS 1500 with One Heat Exchanger (insulation included in the price)

ATTACK buffer storage tanks with heat exchanger form a complete range of five solutions that differ from each other in the method of domestic hot water (DHW) preparation and the number of built-in heat exchangers for charging heating water. This exact choice determines how easily and at what cost you can connect the tank to a heat pump, a wood gasification boiler, a gas boiler, or solar collectors:

• AS – tank with one heat exchanger, purely heating buffer storage. It has no built-in DHW preparation inside, it serves exclusively for buffering heating water and hydraulic separation of the heat source (e.g. a heat pump or a wood gasification boiler) from the heating circuit. In this case, hot water preparation is handled by an external storage tank (e.g. the ATTACK Z range).
• HR – tank with a built-in enamelled DHW storage tank of 160 l inside the buffer tank body (a "tank-in-tank" principle). It does not contain any additional heat exchanger – heating water is fed directly into the buffer tank, which is why it is especially suitable for heat sources that do not require hydraulic separation (typically solid fuel boilers with their own circulation pump).
• HRS – the same construction as HR (built-in enamelled DHW storage tank of 160 l), supplemented with one additional external heat exchanger for charging heating water. Thanks to this heat exchanger, the HRS is also suitable for heat sources requiring hydraulic separation, for example a heat pump.
• TUV – tank with a stainless steel coil inside that provides instantaneous (flow-through) heating of domestic hot water – cold water flows through the coil and is instantly heated, without the need for a separate DHW storage tank. Heating water is fed directly, without any additional heat exchanger.
• TUVS – a combination of TUV (stainless steel coil for instantaneous DHW heating) and one additional external heat exchanger for charging heating water – the most versatile solution in the range, also suitable for heat sources requiring hydraulic separation (heat pump, combination of multiple sources).

ATTACK Buffer Storage Tank AS 1500 with One Heat Exchanger (insulation included in the price) belongs to the range of ATTACK buffer storage tanks with heat exchanger in the 1500-litre volume category. It is the AS – buffer storage tank with one heat exchanger variant – purely heating buffer storage with a single heat exchanger for charging heating water – without built-in domestic hot water preparation. This page describes this specific model in detail, including its technical parameters, recommended heat sources, and the most frequently asked customer questions.

Key Features

• Removable soft insulation, 100 mm thick, in a durable leatherette (PVC) cover – easily removed and reattached during connection servicing, without the need to permanently disturb the tank's surface.
• External heat exchanger for charging heating water with an estimated heat transfer area of approx. 3.6 m², enabling hydraulic separation of the heat source (e.g. a heat pump) from the heating circuit.
• Welded steel body with anti-corrosion internal treatment, rated for a max. operating pressure of 3 bar and water temperature up to 95 °C.
• Prepared connection with G 6/4" thread for installing an ATTACK TH electric heating element (2 – 6 kW) as a backup or supplementary heat source.
• Multiple connections (approx. 7 in total) for connecting heat source(s), heating circuits, temperature sensors, and air venting – exact layout of connections according to manufacturing documentation.
• Compact footprint with a height/diameter ratio optimised to pass through standard doors and staircases during installation into a boiler room or utility room.
• Possibility of combining several heat sources simultaneously (heat pump, wood gasification boiler, solar system, electric element) thanks to multiple connection levels on the tank shell.
• Made in Slovakia, 24-month warranty from commissioning (max. 30 months from dispatch from production).

Technical Parameters

Installation Recommendations

Thanks to the removable soft insulation with a thickness of 100 mm and a practical leatherette cover, the tank retains water temperature for a long time even outside the heating season, and accessing the insulation during connection servicing is easy – the insulation can be removed and reattached at any time without damage. Thanks to its single heat exchanger, the AS tank is particularly suitable where it is necessary to hydraulically separate one heat source (most often a heat pump or an ATTACK DPX/SLX wood gasification boiler) from the heating circuit, while hot water preparation is handled separately – for example by an external indirect storage tank from the ATTACK Z range (e.g. Z200HP, Z300HP, Z200SOL, Z300SOL) connected to the same heat source.

The AS1500K tank is suitable for use with ATTACK heat sources – with ATTACK DPX/SLX wood gasification boilers (which require heating water buffering due to the combustion process), with heat pumps, as well as with ATTACK EKO/PLQ/KLQ/E/EZ COMBI stationary gas cast-iron boilers, which require an external indirect storage tank for DHW preparation (these boilers do not include a storage tank themselves). We always recommend having the exact sizing of pipework, pumps, and safety fittings assessed by an authorised heating technician according to the project documentation of the specific building.

When installing, allow sufficient space around the tank for service access to connections, sensors, and any electric heating element. We recommend installing a safety valve, an expansion vessel, and an air vent at the highest point of the system in accordance with applicable standards for closed heating systems.

How to Correctly Size the Buffer Tank Volume

The buffer tank volume should be based primarily on the output of the heat source, the heat loss of the heated building, and the mode of operation. For wood gasification boilers (e.g. ATTACK DPX/SLX), it is generally recommended to allow approximately 20 – 40 litres of buffer storage per 1 kW of boiler output, so that the boiler can burn out at full output even outside of immediate heat demand in the house. For heat pumps, the volume is more a matter of hydraulic balancing of the circuit and the number of heating zones, and usually a smaller volume than for wood boilers is sufficient. The AS1500K model with a volume of 1500 litres is roughly suitable for a heat source with an output in the corresponding range – however, we always recommend having the exact calculation performed by a heating technician based on the energy label or heat calculation of the specific building, not just based on a table estimate.

Other Volumes in the Same AS Variant

If a volume of 1500 litres is not exactly what you are looking for, we also offer the same design solution (purely heating buffer storage with a single heat exchanger for charging heating water – without built-in domestic hot water preparation) in our e-shop in other volume ranges:

• ATTACK Buffer Storage Tank AS 500 with One Heat Exchanger (insulation included in the price) – 500 l
• ATTACK Buffer Storage Tank AS 800 with One Heat Exchanger (insulation included in the price) – 800 l
• ATTACK Buffer Storage Tank AS 1000 with One Heat Exchanger (insulation included in the price) – 1000 l

A larger volume means a longer buffering time and fewer charging/discharging cycles per day, which spares the heat source, but also requires more space in the boiler room and a higher purchase price. A smaller volume, on the other hand, is cheaper and more compact, but if undersized, the heat source may switch on more frequently.

Maintenance and Operation

The AS1500K buffer tank requires minimal maintenance – we recommend checking the tightness of all connections and fittings, the function of the safety valve, and the condition of the insulation once a year. For tanks with a stainless steel coil (TUV/TUVS), it is advisable to occasionally check the flow rate, and in areas with harder water, consider filtration at the cold water inlet, which will extend the life of the coil and maintain stable flow performance. For variants with a built-in storage tank (HR/HRS), we recommend following standard DHW storage tank maintenance practices, including occasional inspection of the anode, if included in the design. The removable insulation allows quick and safe access for all these service tasks without permanent damage.

Before first commissioning, we recommend having the system filled, vented, and set up by an authorised technician, who will also confirm the commissioning date that is decisive for the warranty period.

Safety and Standards

The AS1500K tank is intended for operation in closed heating systems and must always be supplemented with a safety valve with the appropriate opening pressure, an expansion vessel of sufficient volume, and an air vent at the highest point of the circuit. Installation, connection, and initial commissioning may only be carried out by a person with the appropriate authorisation in accordance with applicable legislation and technical standards for pressure vessels and heating systems. Failure to comply with these principles may lead to limitation or loss of warranty.

Delivery and Installation

We deliver the AS1500K tank to Slovakia by standard transport on pallets; for larger volumes (from approx. 800 l upwards), we recommend checking in advance whether doors and corridors along the route to the boiler room are wide enough – the weight and dimensions in the parameter table are approximate estimates, and we will gladly confirm the exact values for a specific unit before ordering. We recommend entrusting the actual connection to the heat source, electric heating element, and control system to a professional installation company.

Who This Solution Is Suitable For

We recommend the AS1500K tank with a volume of 1500 litres especially for family houses and smaller facilities that want to efficiently buffer heating water while also addressing domestic hot water preparation in the manner typical of the chosen series (AS – buffer storage tank with one heat exchanger). We recommend consulting the specific choice of volume and variant (AS/HR/HRS/TUV/TUVS) with a heating technician based on the building's heat loss, the number of people in the household, the chosen heat source(s), and the desired level of hot water comfort.

Frequently Asked Questions

What is the difference between the AS1500K tank and the other types in the AS/HR/HRS/TUV/TUVS range?
The AS1500K tank has purely heating buffer storage with a single heat exchanger for charging heating water – without built-in domestic hot water preparation. The other types in the range differ mainly in whether they have a built-in DHW storage tank (HR, HRS), a stainless steel coil for instantaneous heating (TUV, TUVS), or no hot water preparation at all (AS), and in how many external heat exchangers for charging heating water they contain (0 or 1).

What volume of AS1500K tank do I need for a typical family household?
The tank with a volume of 1500 litres is intended for households and buildings that require buffering corresponding roughly to this output and consumption range. We always recommend calculating the exact volume based on the building's heat loss, heat source output, and number of people in the household – we are happy to help you choose based on specific input data.

What is the area of the heat exchanger for charging heating water?
The AS1500K tank has a heat exchanger with an estimated heat transfer area of approximately 3.6 m², which, at typical heat source inlet temperatures, is sufficient for efficiently charging the buffered volume of water within a reasonable time. The exact heat exchanger performance depends on the temperature difference and flow rate on the heat source side.

Is the AS1500K tank suitable for a heat pump?
Yes, the tank has an external heat exchanger for charging heating water, which provides the necessary hydraulic separation of the heat pump circuit from the house's heating circuit – standard connection to ATTACK heat pumps as well as those from other manufacturers.

What is the maximum operating pressure and temperature load of the tank?
The buffer section of the tank is rated for a max. operating pressure of 3 bar and a max. water temperature of 95 °C. The heat exchanger/coil circuit withstands comparable values; you will find the exact maximum parameters in the technical table below and always in the accompanying documentation supplied with the tank.

How is the AS1500K tank insulated, and can the insulation be removed later for servicing?
The tank is equipped with soft removable insulation, 100 mm thick, in a leatherette cover, which is easily removed and reattached using hook-and-loop fasteners/straps without damage – useful when connecting fittings, performing service work, or additionally installing sensors and heating elements.

Can the tank be combined with several heat sources at once (e.g. heat pump and solar)?
Yes, this is one of the main functions of a buffer storage tank with heat exchanger – it allows combining several heat sources (heat pump, wood gasification boiler, solar system, electric heating element) into a single buffer tank body. We recommend having the exact connection scheme and the required number of connections designed by a heating technician according to the specific combination of sources.

Is it possible to install an electric heating element later?
Yes, the tank has a prepared connection with G 6/4" thread for ATTACK TH electric heating elements (e.g. TH100, TH102, TH103, TH107 with an output of 2 – 6 kW), which serve as a backup or supplementary heat source.

Is the price difference between AS, HR, HRS, TUV, and TUVS just about additional equipment?
Yes, the price difference between the individual variants of the same volume reflects the amount of built-in components – a built-in enamelled DHW storage tank (HR/HRS), a stainless steel coil (TUV/TUVS), and/or an additional external heat exchanger (HRS/TUVS compared to HR/TUV). The more functions the tank integrates, the higher the purchase price, but at the same time you don't need to buy and install separate additional equipment.

How does ordering and delivery of the AS1500K tank work?
After ordering, we dispatch the tank from the manufacturing warehouse in Slovakia, and we will inform you of the delivery date by email or phone. If interested, we can also recommend compatible accessories (ATTACK TH electric heating elements, circulation pumps, controls) so that you receive a complete functional set in a single order.

Warranty

We provide a 24-month warranty period for the AS1500K buffer tank from the date of commissioning, but no more than 30 months from the date of dispatch from production. If you have any questions about choosing, connecting, or servicing the tank, please do not hesitate to contact our sales department – we are happy to help design the entire system, including the heat source, circulation pumps, and controls.