ATTACK AS 800 Storage Tank with One Heat Exchanger (insulation included in price)

Product detailed description

ATTACK Accumulation Tank AS 800 with One Heat Exchanger (insulation included)

ATTACK accumulation tanks with heat exchanger form a comprehensive range of five solutions that differ from each other in the way domestic hot water (DHW) is prepared and in the number of built-in heat exchangers for charging heating water. This choice is exactly what 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 – a tank with one heat exchanger, purely heating accumulation. It has no built-in DHW preparation inside; it serves exclusively for accumulating heating water and hydraulically separating the heat source (e.g. a heat pump or a gasification boiler) from the heating circuit. In this case, hot water preparation is handled by an external tank (e.g. the ATTACK Z series).
• HR – a tank with a built-in enamelled DHW tank with a volume of 160 l inside the accumulation vessel (a "tank-in-tank" principle). It contains no additional heat exchanger – heating water is fed directly into the accumulation tank, so it is best suited 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 160 l DHW tank), supplemented by 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, such as a heat pump.
• TUV – a tank with a stainless steel coil inside, which provides flow-through (instantaneous) heating of domestic hot water – cold water flows through the coil and is heated immediately, without the need for a separate DHW tank. Heating water is fed in directly, without an additional heat exchanger.
• TUVS – a combination of TUV (stainless steel coil for flow-through 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 Accumulation Tank AS 800 with One Heat Exchanger (insulation included) belongs to the ATTACK accumulation tank with heat exchanger range in the 800-litre volume category. It is the AS – accumulation tank with one heat exchanger variant – purely heating accumulation with one heat exchanger for charging heating water – without built-in domestic hot water preparation. This page describes exactly this particular model, including its technical parameters, recommended heat sources, and the most frequently asked customer questions.

Key Features

• Removable soft insulation with a thickness of 100 mm in a durable leatherette (PVC) cover – it is easily removed and put back on during connection servicing, without any need for permanent damage to the tank surface.
• External heat exchanger for charging heating water with an estimated heat transfer area of approx. 2.5 m², enabling hydraulic separation of the heat source (e.g. a heat pump) from the heating circuit.
• Steel welded body with anti-corrosion internal treatment, designed for a max. operating pressure of 3 bar and water temperature up to 95 °C.
• Prepared port with G 6/4" thread for installing an ATTACK TH electric heating cartridge (2 – 6 kW) as a backup or supplementary heat source.
• Multiple ports (approx. 6 in total) for connecting the heat source(s), heating circuits, temperature sensors, and venting – exact port layout according to manufacturing documentation.
• Compact footprint with a height/diameter ratio optimised for passing 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 cartridge) 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 over the long term even outside the heating season, and accessing the insulation for connection servicing is easy – the insulation can be removed and put back on at any time without damage. Thanks to its single heat exchanger, the AS tank is best suited primarily 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 indirectly heated tank from the ATTACK Z series (e.g. Z200HP, Z300HP, Z200SOL, Z300SOL) connected to the same heat source.

The AS800K tank is suitable for a system with ATTACK heat sources – with ATTACK DPX/SLX wood gasification boilers (which require heating water accumulation due to the combustion process), with heat pumps, as well as with ATTACK EKO/PLQ/KLQ/E/EZ COMBI stationary cast iron gas boilers, which need an external indirectly heated tank for DHW preparation (these boilers themselves do not include a tank). We always recommend having the exact sizing of pipework, pumps, and safety fittings assessed by a qualified heating engineer according to the project documentation of the specific building.

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

How to Correctly Size the Accumulation Tank Volume

The accumulation tank volume should be based primarily on the heat source output, the heat loss of the heated building, and the mode of operation. For wood gasification boilers (e.g. ATTACK DPX/SLX), a guideline of approximately 20 – 40 litres of accumulation per 1 kW of boiler output is usually recommended, so that the boiler can burn out at full output even outside the immediate heat demand of the house. For heat pumps, the volume is more a matter of hydraulic balancing of the circuit and the number of heating zones, and a smaller volume is usually sufficient than with wood boilers. The AS800K model with a volume of 800 litres is suitable as a guideline for a heat source with output in the corresponding range – however, we always recommend having the exact calculation done by a heating engineer based on the energy label or a heat loss calculation of the specific building, not just a table estimate.

Other Volumes in the Same AS Variant

If a volume of 800 litres is not exactly what you are looking for, we also offer the same design solution (purely heating accumulation with one heat exchanger for charging heating water – without built-in domestic hot water preparation) in our e-shop in other volume ranges:

• ATTACK Accumulation Tank AS 500 with One Heat Exchanger (insulation included) – 500 l
• ATTACK Accumulation Tank AS 1000 with One Heat Exchanger (insulation included) – 1000 l
• ATTACK Accumulation Tank AS 1500 with One Heat Exchanger (insulation included) – 1500 l

A larger volume means a longer accumulation time and fewer charge/discharge cycles per day, which saves the heat source, but also requires more space in the boiler room and a higher purchase price. A smaller volume is, on the other hand, cheaper and more compact, but if undersized, the heat source may cycle on/off more frequently.

Maintenance and Operation

The AS800K accumulation tank requires minimal maintenance – we recommend checking the tightness of all ports and connections, 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 hard water areas to consider filtration at the cold water inlet, which extends the coil's service life and maintains stable flow performance. For variants with a built-in tank (HR/HRS), we recommend following the usual DHW tank maintenance principles, including occasional inspection of the anode, if included in the design. The removable insulation allows quick and safe access for all these service operations without any need for permanent damage.

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

Safety and Standards

The AS800K tank is intended for operation in closed heating systems and must always be supplemented with a safety valve with an appropriate opening pressure, an expansion vessel with sufficient volume, and a venting valve at the highest point of the circuit. Installation, connection, and first commissioning may only be carried out by a person with appropriate qualification in accordance with applicable legislation and technical standards for pressure vessels and heating systems. Failure to observe these principles may lead to a restriction or loss of warranty.

Delivery and Installation

We deliver the AS800K tank to Slovakia by standard transport on pallets; for larger volumes (from approx. 800 l upwards) we recommend checking in advance the passability of doors and corridors on the route to the boiler room – the weight and dimensions in the parameters 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, the electric heating cartridge, and the control system to a professional installation company.

Who This Solution Is Suitable For

We recommend the AS800K tank with a volume of 800 litres primarily for family homes and smaller premises that want to efficiently accumulate heating water while also handling domestic hot water preparation in the manner typical of the chosen series (AS – accumulation tank with one heat exchanger). We recommend consulting the specific choice of volume and variant (AS/HR/HRS/TUV/TUVS) with a heating engineer based on the heat loss of the building, the number of people in the household, the chosen heat source(s), and the desired comfort of hot water preparation.

Frequently Asked Questions

What is the difference between the AS800K tank and the other types in the AS/HR/HRS/TUV/TUVS range?
The AS800K tank is purely heating accumulation with one 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 tank (HR, HRS), a stainless steel coil for flow-through 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 the AS800K tank do I need for a typical family household?
A tank with a volume of 800 litres is intended for households and buildings requiring accumulation corresponding approximately to this output and consumption range. We always recommend calculating the exact volume based on the building's heat loss, the heat source output, and the 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 AS800K tank has a heat exchanger with an estimated heat transfer area of approximately 2.5 m², which, at typical heat source inlet temperatures, is sufficient for effectively charging the accumulated volume of water within a reasonable time. The exact performance of the heat exchanger depends on the temperature gradient and flow rate on the heat source side.

Is the AS800K 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 – a common connection for ATTACK heat pumps as well as those of other manufacturers.

What is the maximum operating pressure and temperature load of the tank?
The accumulation part of the tank is designed 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 also in the accompanying documentation supplied with the tank.

How is the AS800K tank insulated, and can the insulation be removed later for servicing?
The tank is equipped with soft removable insulation with a thickness of 100 mm in a leatherette cover, which is easily removed and put back on using hook-and-loop fasteners/straps without damage – useful when connecting ports, performing service work, or additionally installing sensors and heating cartridges.

Can the tank be combined with several heat sources at once (e.g. a heat pump and solar)?
Yes, this is one of the main purposes of an accumulation tank with a heat exchanger – it allows several heat sources (heat pump, wood gasification boiler, solar system, electric heating cartridge) to be combined into one accumulation vessel. We recommend having the exact connection and the number of required ports designed by a heating engineer according to the specific combination of sources.

Is it possible to additionally fit an electric heating cartridge?
Yes, the tank has a prepared port with a 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 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 a tank integrates, the higher its purchase price, but at the same time you do not need to buy and install separate additional devices.

How does ordering and delivery of the AS800K tank work?
After ordering, we dispatch the tank from the production warehouse in Slovakia, and we will inform you of the delivery date by e-mail or phone. If you are interested, we can also recommend compatible accessories (ATTACK TH electric heating cartridges, circulation pumps, controls) so that you get a complete, functional system in a single order.

Warranty

We provide a warranty period of 24 months from the commissioning date for the AS800K accumulation tank, 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.