ATTACK HRS 800 Buffer Tank with Built-in 160L DHW Cylinder and One Heat Exchanger (insulation included)

Product detailed description

ATTACK Buffer Tank HRS 800 with built-in 160L DHW tank and one heat exchanger (insulation included in price)

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

• AS – tank with one heat exchanger, purely for heating water accumulation. It has no DHW preparation built in, and serves exclusively for accumulating heating water and hydraulically separating the heat source (e.g. a heat pump or gasification boiler) from the heating circuit. In this case, hot water preparation is handled by an external tank (e.g. the ATTACK Z range).
• HR – tank with a built-in enamelled DHW tank with a volume of 160 l inside the buffer body (a "tank-in-tank" principle). It contains no additional heat exchanger – heating water is fed directly into the buffer tank, so it is best suited to 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 tank, 160 l), complemented by one additional external heat exchanger for charging heating water. Thanks to this heat exchanger, HRS is also suitable for heat sources requiring hydraulic separation, such as a heat pump.
• TUV – tank with a stainless steel coil inside, which ensures instantaneous (flow-through) 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 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 Tank HRS 800 with built-in 160L DHW tank and one heat exchanger (insulation included in price) belongs to the ATTACK range of buffer tanks with heat exchanger in the 800-litre volume category. It is the HRS – buffer tank with built-in DHW tank and heat exchanger variant – a built-in enamelled DHW tank with a volume of 160 l inside the tank, complemented by one additional external heat exchanger for charging heating water. 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 100 mm thick in a durable leatherette (PVC) cover – easy to remove and reattach during connection servicing, without permanently disturbing the tank surface.
• Built-in enamelled domestic hot water tank with a volume of 160 l inside the buffer body (a "tank-in-tank" principle) – hot water prepared directly within the tank body without the need for a separate external boiler.
• External heat exchanger for charging heating water with an estimated heat exchange area of approx. 2.6 m², enabling hydraulic separation of the heat source (e.g. a heat pump) from the heating circuit.
• Steel welded body with corrosion-resistant internal treatment, designed for a max. operating pressure of 3 bar and water temperature up to 95 °C.
• A ready-made G 6/4" threaded port for installation of an ATTACK TH electric heating element (2 – 6 kW) as a backup or supplementary heat source.
• Multiple ports (approx. 9 in total) for connecting heat source(s), heating circuits, temperature sensors and air venting – exact port layout according to manufacturing documentation.
• Compact footprint with a height/diameter ratio optimised to pass through standard doors and staircases when installing in a boiler room or utility room.
• Option to combine several heat sources simultaneously (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 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 well even outside the heating season, and accessing the insulation for connection servicing is simple – the insulation can be removed and reattached at any time without damage. The added external heat exchanger makes the HRS a more versatile choice than the HR – it is also suitable for heat sources requiring hydraulic separation, such as a heat pump, while retaining the convenience of the built-in 160 l DHW tank without the need for an external boiler.

The HRS800K tank is suitable for use 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 require an external indirectly heated tank for DHW preparation (these boilers do not include a tank themselves). We always recommend having the precise sizing of piping, pumps and safety fittings assessed by an authorised heating technician according to the design documentation of the specific building.

When installing, allow sufficient space around the tank for service access to the ports, 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 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 general recommendation is approx. 20 – 40 litres of accumulation per 1 kW of boiler output, 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 balancing of the circuit and the number of heating zones, and a smaller volume is usually sufficient than with wood boilers. The HRS800K model with a volume of 800 litres is orientationally suitable for a heat source with output in the corresponding range – however, we always recommend having the exact calculation made by a heating technician based on the energy label or heat loss calculation of the specific building, not just a table estimate.

Other volumes in the same HRS variant

If 800 litres is not exactly what you are looking for, we also offer the same design solution (a built-in enamelled DHW tank with a volume of 160 l inside the tank, complemented by one additional external heat exchanger for charging heating water) in our shop in other volume ranges:

• ATTACK Buffer Tank HRS 600 with built-in 160L DHW tank and one heat exchanger (insulation included in price) – 600 l
• ATTACK Buffer Tank HRS 1000 with built-in 160L DHW tank and one heat exchanger (insulation included in price) – 1000 l

A higher 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 lower volume is cheaper and more compact, but if undersized, the heat source may cycle on and off more frequently.

Maintenance and operation

The HRS800K buffer tank requires minimal maintenance – we recommend checking the tightness of all ports and connections, the functionality of the safety valve, and the condition of the insulation once a year. For tanks with a stainless steel coil (TUV/TUVS), it is a good idea to occasionally check the flow rate, and in harder water areas consider filtration at the cold water inlet, which extends the life of the coil and maintains stable flow performance. For variants with a built-in tank (HR/HRS), we recommend following the usual maintenance principles for DHW tanks, including occasional checking of the anode, if included in the design. The removable insulation allows quick and safe access for all of 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, which is decisive for the start of the warranty period.

Safety and standards

The HRS800K tank is designed for operation in closed heating systems and must always be complemented by a safety valve with the appropriate opening pressure, an expansion vessel with 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 relevant qualification in accordance with applicable legislation and technical standards for pressure vessels and heating systems. Failure to observe these principles may lead to the limitation or loss of the warranty.

Delivery and installation

We deliver the HRS800K tank within Slovakia by standard palletised transport; for larger volumes (from approx. 800 l upwards), we recommend checking in advance the clearance of doors and corridors on the route to the boiler room – the weight and dimensions in the parameter table are approximate estimates, and we will be happy to 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 HRS800K tank with a volume of 800 litres primarily for family houses and smaller facilities that want to efficiently accumulate heating water while also addressing domestic hot water preparation in the manner typical of the chosen series (HRS – buffer tank with built-in DHW tank and heat exchanger). We recommend consulting with a heating technician on the specific choice of volume and variant (AS/HR/HRS/TUV/TUVS) 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 HRS800K tank and other types in the AS/HR/HRS/TUV/TUVS range?
The HRS800K tank has a built-in enamelled DHW tank with a volume of 160 l inside the tank, complemented by one additional external heat exchanger for charging heating water. The other types in the range differ mainly in whether they have a built-in DHW 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 the HRS800K tank do I need for a typical family household?
The 800-litre tank is designed for households and buildings requiring accumulation 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 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 HRS800K tank has a heat exchanger with an estimated heat exchange area of approximately 2.6 m², which, at typical heat source inlet temperatures, is sufficient for efficiently charging the accumulated volume of water within a reasonable time. The exact performance of the heat exchanger depends on the temperature difference and flow rate on the heat source side.

Is the built-in 160 l tank enough hot water for the whole household?
The built-in enamelled tank 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 simultaneously), we recommend adding an external DHW tank or considering the TUV/TUVS variant with instantaneous heating, which is not limited by volume.

Is the HRS800K 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 from other manufacturers.

What is the maximum operating pressure and temperature load of the tank?
The buffer section 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; exact maximum parameters can be found in the technical table below and always also in the accompanying documentation supplied with the tank.

How is the HRS800K tank insulated, and can the insulation be removed later for servicing?
The tank is fitted 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 ports, during servicing, or when additionally installing sensors and heating elements.

Can the tank be combined with several heat sources at once (e.g. a heat pump and solar)?
Yes, that is one of the main purposes of a buffer tank with 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 number of required ports designed by a heating technician according to the specific combination of sources.

Is it possible to additionally install an electric heating element?
Yes, the tank has a ready-made G 6/4" threaded port 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 don't need to buy and install separate additional devices.

How does ordering and delivery of the HRS800K 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 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 HRS800K 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 whole system, including the heat source, circulation pumps and controls.