ATTACK HR 800 Storage Tank with Built-in Enamelled 160L DHW Cylinder (insulation included)

Product detailed description

ATTACK Buffer Tank HR 800 with built-in enamelled 160L DHW cylinder (insulation included in price)

ATTACK buffer tanks with heat exchanger form a complete range of five solutions that differ from one another in the way domestic hot water (DHW) is prepared and in the number of built-in heat exchangers for charging the heating water. It is precisely this choice that 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 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. DHW preparation is in that case handled by an external cylinder (e.g. the ATTACK Z range).
• HR – tank with a built-in enamelled DHW cylinder with a volume of 160 l inside the buffer body ("tank-in-tank" principle). It does not contain any additional heat exchanger – heating water is fed directly into the buffer tank, therefore it is best suited for heat sources that do not require hydraulic separation (typically solid fuel boilers with their own circulation pump).
• HRS – same construction as HR (built-in enamelled 160 l DHW cylinder), supplemented with one additional external heat exchanger for charging the heating water. Thanks to this heat exchanger, HRS is also suitable for heat sources requiring hydraulic separation, for example a heat pump.
• TUV – tank with a stainless steel coil inside, which provides instantaneous (flow-through) heating of domestic hot water – cold water flows through the coil and is immediately heated, without the need for a separate DHW cylinder. Heating water is fed in 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 the heating water – the most versatile solution in the range, suitable also for heat sources requiring hydraulic separation (heat pump, combination of multiple sources).

ATTACK Buffer Tank HR 800 with built-in enamelled 160L DHW cylinder (insulation included in price) belongs to the range of ATTACK buffer tanks with heat exchanger in the 800-litre volume category. It is the HR – buffer tank with built-in enamelled DHW cylinder variant – a built-in enamelled DHW cylinder with a volume of 160 l inside the tank ("tank-in-tank" principle), without any additional heat exchanger – heating water is fed in directly. This page describes precisely this specific model, 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 refitted during service work on connections, without permanently damaging the tank surface.
• Built-in enamelled domestic hot water cylinder with a volume of 160 l inside the buffer body ("tank-in-tank" principle) – hot water prepared directly within the tank body without the need for a separate external boiler.
• No heat exchanger on the heating water side – direct connection of the heat source with its own circulation pump (typically a solid fuel boiler), simpler and cheaper installation.
• Welded steel body with anti-corrosion interior treatment, designed for a max. operating pressure of 3 bar and a water temperature of up to 95 °C.
• Prepared port with G 6/4" thread for installing an ATTACK TH electric heating element (2 – 6 kW) as a backup or supplementary heat source.
• Multiple ports (approx. 8 in total) for connecting heat source(s), heating circuits, temperature sensors and venting – exact port layout according to the manufacturer's documentation.
• Compact footprint with height/diameter ratio optimised for passing through standard doors and staircases when installing in a boiler room or utility room.
• Possibility of combining several heat sources at the same time (heat pump, wood gasification boiler, solar system, electric heating element) thanks to multiple connection levels on the tank shell.
• Made in Slovakia, 24-month warranty from commissioning (max. 30 months from factory dispatch).

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 refitted at any time without damage. Since HR has no heat exchanger for charging the heating water, it is best suited for heat sources with their own circulation pump and without the need for hydraulic separation – typically solid fuel boilers (wood, coal) or ATTACK DPX/SLX gasification boilers connected directly into the tank circuit. The built-in 160 l enamelled cylinder covers the typical operating hot water consumption of a household without the need for an additional cylinder.

The HR800K tank is suitable for use in a set 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 indirect DHW cylinder (these boilers do not include a cylinder themselves). We always recommend having the exact sizing of piping, pumps and safety fittings assessed by an authorised heating technician according to the project documentation of the specific building.

When installing, allow for sufficient space around the tank for service access to ports, sensors and any electric heating element. 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 buffer tank volume

The buffer 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 when there is no immediate heat demand in the house. For heat pumps, the volume is more a matter of hydraulic circuit balancing and the number of heating zones, and usually a smaller volume than for wood boilers is sufficient. The HR800K model with a volume of 800 litres is suitable as a rough guide for a heat source with output in the corresponding range – however, we always recommend having the exact calculation done by a heating technician based on the energy label or a heat calculation of the specific building, not just a table estimate.

Other volumes in the same HR variant

If a volume of 800 litres is not exactly what you are looking for, we also offer the same design solution (built-in enamelled DHW cylinder with a volume of 160 l inside the tank ("tank-in-tank" principle), without any additional heat exchanger – heating water is fed in directly) in our shop in other volume ranges:

• ATTACK Buffer Tank HR 600 with built-in enamelled 160L DHW cylinder (insulation included in price) – 600 l
• ATTACK Buffer Tank HR 1000 with built-in enamelled 160L DHW cylinder (insulation included in price) – 1000 l

A higher volume means a longer accumulation time and fewer charge/discharge cycles per day, which is gentler on the heat source, but also requires more space in the boiler room and a higher purchase price. A lower 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 HR800K buffer 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 harder water areas, 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 cylinder (HR/HRS), we recommend following the usual maintenance principles for DHW cylinders, including occasional checking of the anode, if included in the design. The removable insulation allows quick and safe access for all these service tasks without permanently damaging it.

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 determines the start of the warranty period.

Safety and standards

The HR800K 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 a venting valve at the highest point of the circuit. Installation, connection and initial commissioning may only be carried out by a person with the appropriate qualification, in accordance with applicable legislation and technical standards for pressure vessels and heating systems. Failure to observe these principles may lead to limitation or loss of warranty.

Delivery and installation

We deliver the HR800K tank within Slovakia by standard pallet transport; for larger volumes (from approx. 800 l upwards), we recommend checking in advance the passability of doors and corridors along 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 leaving 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 HR800K tank with a volume of 800 litres especially for family houses 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 (HR – buffer tank with built-in enamelled DHW cylinder). 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 required hot water comfort.

Frequently asked questions

What is the difference between the HR800K tank and other types in the AS/HR/HRS/TUV/TUVS range?
The HR800K tank has a built-in enamelled DHW cylinder with a volume of 160 l inside the tank ("tank-in-tank" principle), without any additional heat exchanger – heating water is fed in directly. Other types in the range differ mainly in whether they have a built-in DHW cylinder (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 the HR800K tank do I need for a typical family household?
The tank with a volume of 800 litres is intended for households and buildings that require accumulation corresponding roughly 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.

Why does the HR800K tank have no heat exchanger for charging the heating water?
This type is designed for direct connection of the heat source (without the need for hydraulic separation), typically to a solid fuel boiler with its own circulation pump. If you are planning a heat source requiring hydraulic separation (e.g. a heat pump), choose instead the variant with an added heat exchanger (HRS instead of HR, or TUVS instead of TUV).

Is the built-in 160 l cylinder enough hot water for the whole household?
The built-in enamelled cylinder with a volume of 160 l covers the typical operating consumption of a standard household (approx. 3 – 5 people) with adequate reheating. For higher peak consumption (e.g. several bathrooms in use at once), we recommend adding an external DHW cylinder or considering the TUV/TUVS variant with instantaneous heating, which is not limited by volume.

Is the HR800K tank suitable for a heat pump?
Direct connection without a heat exchanger is intended rather for sources with their own circulation pump (e.g. solid fuel boilers). For a heat pump, which typically requires hydraulic separation, we recommend choosing the related variant with an added heat exchanger (HRS instead of HR, or TUVS instead of TUV) from the same ATTACK range.

What is the maximum operating pressure and temperature load of the tank?
The buffer 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 HR800K tank insulated, and can the insulation later be removed for servicing?
The tank is fitted with soft removable insulation with a thickness of 100 mm in a leatherette cover, which is easily removed and refitted using hook-and-loop fasteners/straps without damage – useful when connecting ports, performing service work, or additionally installing sensors and heating elements.

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

Is it possible to additionally fit an electric heating element?
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 only due to 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 cylinder (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 the 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 HR800K 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 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 HR800K buffer tank from the date of commissioning, but no more than 30 months from the date of dispatch from the factory. 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 set, including the heat source, circulation pumps and controls.