ATTACK AK 1000 Storage Tank (insulation included in the price)

Product detailed description

Why the storage tank determines heating efficiency

ATTACK Storage Tank AK 1000 (insulation included in price) is a steel storage (buffer) tank with a volume of 1000 litres, designed for storing hot heating water from any heat source - a wood gasification boiler, heat pump, electric boiler, gas boiler or solar collectors. It is a tank without a built-in heat exchanger (sometimes also referred to as a "hydraulic separator" or "buffer tank"), which serves purely to store heating water - heating of domestic hot water (DHW) with this type of tank is handled externally, for example via a storage water heater or flow module.

The greatest benefit of a storage tank is seen when combined with a solid fuel gasification boiler, such as ATTACK DPX or ATTACK SLX. These boilers achieve their highest efficiency and cleanest combustion precisely when burning at full, rated output - i.e. when they burn a full load of wood "in one go" without throttling the air supply. Without a storage tank, the boiler would often have to operate in a throttled mode (to prevent overheating of the system), which leads to worse combustion, higher tar formation and shorter lifespan of both the boiler and chimney. With the ATTACK Storage Tank AK 1000 (insulation included in price), the boiler burns the fuel at full output at once and the excess heat is stored in the water reserve in the tank - from there the heating system gradually draws it according to the household's current needs, even several hours after the boiler has burned out.

The same principle also works with an electric boiler or heat pump: the 1000 l tank allows the heat source to operate in longer, less frequent cycles instead of constantly switching on and off at short intervals, which extends the lifespan of the compressor/heating elements and reduces energy consumption. This volume is suitable for larger family houses, two-generation houses or smaller facilities where multiple heat sources are combined (e.g. a wood gasification boiler together with a heat pump or solar collectors) and larger fluctuations between heat production and consumption need to be balanced.

Key features of the AK1000K tank

• 1000-litre volume - designed to provide a sufficient heat reserve between individual heating cycles at the recommended heat source output of 40 - 50 kW.
• Soft, removable polyester insulation 100 mm thick - significantly reduces heat losses to the surroundings during long-term storage of hot water, while it can be easily unfastened for inspection or servicing of the tank and connections.
• Outer insulation cover made of leatherette (PVC fabric) in a silver-grey design - resistant to abrasion and easy to maintain, visually blends into the boiler room interior rather than looking like a "technical" element.
• 6 connection ports distributed around the shell and on the top/bottom of the tank, allowing connection of the heat source, heating circuits, an additional electric heating element (booster heating), venting, draining and temperature sensors.
• Steel shell with an internal corrosion-resistant surface finish, rated for a max. operating pressure of 3 bar and a max. temperature of 95 °C - a safe margin above typical operating temperatures of heating water (60-80 °C).
• Suitable for vertical position thanks to feet/stand, which at this volume facilitates precise temperature layering (stratification) - warmer water naturally stays on top, cooler water at the bottom, increasing the usability of the accumulated heat.
• Possibility of additional installation of an electric heating element (e.g. ATTACK TH100, TH102, TH103 or TH107) directly into one of the tank's connection ports - suitable as a backup or supplementary heat source outside the heating season or in case of a main heat source failure.
• Without a built-in heat exchanger - the tank is designed purely for heating water accumulation; if you also need DHW preparation via a built-in heat exchanger, see our range of AS/HR/HRS/TUV/TUVS tanks with heat exchanger.

Technical parameters

Note: the dimensions and weight of the empty tank are approximate estimates corresponding to the given volume; we recommend verifying the exact dimensions before installation (e.g. in the case of limited boiler room space or narrow doors/staircases) directly with the seller before ordering.

How to correctly choose the volume of a storage tank

The most common recommended rule when choosing a storage tank for a solid fuel gasification boiler is: for every 1 kW of the boiler's rated output, allow approximately 20 to 25 litres of storage volume. This rule is based on the fact that the boiler burns one load of fuel at full output in approximately 1.5 to 3 hours, and the heat from this load needs to be stored somewhere until the heating system gradually consumes it. For a tank with a volume of 1000 litres, this means it is suitable for a heat source with an output of approximately 40 to 50 kW.

If, for example, you have a wood gasification boiler with an output in this range (from the ATTACK range, these are for example some models of the DPX or SLX series - both Standard and Profi versions), the tank ATTACK Storage Tank AK 1000 (insulation included in price) is appropriately sized for your system. For higher boiler output, or if you plan to combine multiple heat sources (e.g. a wood boiler + heat pump, or a boiler + solar collectors), we recommend choosing a larger volume, or connecting several tanks in a cascade - so that the storage volume corresponds to the sum of the outputs of the connected sources.

For a volume of 1000 l, it also holds that the larger the tank, the longer it can deliver heat even after the boiler has completely burned out - with a well-designed and sufficiently large system, it is common for a family house to be able to heat for 12 to 24 hours on a single boiler charge and one storage tank, depending on the outdoor temperature, the heat losses of the house and the temperature gradient of the heating system (lower temperatures, e.g. with underfloor heating, allow a larger portion of the stored heat to be used than high-temperature radiator systems).

It should also be noted that a storage tank is worthwhile even in combination with automatic heat sources such as an electric boiler or heat pump - although these sources can modulate output more smoothly than a solid fuel boiler, they still benefit from the tank by reducing the number of switching cycles, which saves the lifespan of the compressor, circulation pumps and electronics.

Connection, installation and heating options

The ATTACK Storage Tank AK 1000 (insulation included in price) is typically connected as a hydraulically separated buffer element between the heat source and the heating system (radiators, underfloor heating, fan-coil units, etc.) - the heat source charges the tank via one pair of ports, while the heating system draws heat via the other pair, hydraulically separating both circuits so that the system operates more stably even with fluctuating flow on the source side. The remaining ports (there are 6 in total on this tank) serve, for example, for fitting a temperature sensor, air vent, safety valve, or for connecting an additional electric heating element.

The option to fit an electric heating element is a practical solution for periods when you don't want to heat with solid fuel (e.g. outside the main heating season) or as a backup in case of a main heat source failure. Our range includes electric heating elements ATTACK TH100 (2.5 kW), TH102 (4.5 kW), TH103 (6 kW) and TH107 (2 kW), all with their own thermostat and G6/4" thread - compatible with the ports of this storage tank. We recommend choosing the element's output to match the tank's volume and the desired heating-up speed.

When installing the ATTACK Storage Tank AK 1000 (insulation included in price), allow for sufficient handling space in the boiler room - given the diameter with insulation of approximately 1200 mm and a height of approximately 1700 mm (both values approximate, see above), it is necessary to verify in advance the passability of doors, staircases and the room itself. We also recommend leaving a free space of at least 300-500 mm around the tank on the side with the connection ports, to ensure convenient access during servicing, gasket replacement or checking/adding sensors.

We recommend filling the tank only with treated heating water in accordance with the applicable standard (e.g. STN EN 14868 or the boiler manufacturer's recommendation) - hard water with a high mineral content accelerates limescale formation on the inner walls and shortens the lifespan of the entire system, including the boiler and circulation pumps.

Connection with other components of the heating system

The ATTACK Storage Tank AK 1000 (insulation included in price) is only one link in the heating chain. Customers most often combine it with the wood gasification boiler ATTACK DPX or ATTACK SLX (both Standard and Profi versions, output ranges of approximately 15-35 kW), with the boiler output ideally matching the recommended range of 40-50 kW mentioned above. When combined with a heat pump or electric boiler, the tank serves as a hydraulic separator and heat storage, reducing the number of switching cycles of the source. If you also need to prepare domestic hot water, since this particular tank is a version without a heat exchanger, we recommend adding a separate DHW storage water heater to the system (e.g. from the ATTACK Z range - Z100, Z125, Z160, Z200 and others, available in our range), or choosing instead one of the AS/HR/HRS/TUV/TUVS series models, which have a heat exchanger built directly into the tank.

Maintenance and inspection of the tank during operation

The ATTACK Storage Tank AK 1000 (insulation included in price) requires minimal but regular maintenance. We recommend checking once a year (for example before the start of the heating season) the tightness of all 6 connection ports, the condition of the air vent and the safety valve of the heating circuit, as well as the overall condition of the outer insulation cover - the leatherette cover in silver-grey is resistant to normal abrasion, but in case of mechanical damage (e.g. during relocation or handling in the boiler room), we recommend repairing the damaged spot promptly to avoid unnecessary heat losses.

Since this is a tank without a built-in heat exchanger, the inside of the tank only comes into contact with treated heating water, not drinking water - the risk of limescale build-up is thus significantly lower than with DHW storage tanks, but we still recommend once every few years (for example during a system shutdown) visually inspecting the inside of the tank via a revision opening, if the model is equipped with one, or at least monitoring the quality and colour of the heating water during system desludging. Cloudy or rusty water may indicate a need for water treatment or a check of corrosion in the system.

During long-term shutdown (e.g. outside the heating season), it is not necessary to drain the tank - on the contrary, leaving water in the system protects the inner surface from corrosion caused by air exposure. If you plan to take the tank completely out of operation for a longer period, consult a professional installer about the appropriate preservation procedure.

Frequently Asked Questions

Do I also need to buy a heat exchanger for this tank?

No, this AK1000K model cannot be additionally fitted with a built-in heat exchanger - it serves purely for accumulating heating water. If you need to prepare domestic hot water via a heat exchanger in one tank, choose from our AS, HR, HRS, TUV or TUVS series.

How large a boiler can I connect to this tank?

For a volume of 1000 litres, we recommend a heat source with an output of approximately 40 to 50 kW, according to the rule of 20-25 litres of storage per 1 kW of output. For a more powerful source, it is better to choose a larger volume or connect several tanks in a cascade.

Can the tank also be used with a heat pump or electric boiler?

Yes, the AK1000K storage tank works equally well with a heat pump, electric boiler, gas boiler or solar collectors - in every case it reduces the number of switching cycles of the source and balances differences between heat production and consumption.

Is insulation included in the delivery?

Yes, the tank is supplied including soft, removable polyester insulation 100 mm thick and an outer cover made of leatherette in silver-grey.

Can I fit an electric heating element in the tank for booster heating?

Yes, the tank has 6 connection ports, one of which can be used to install an electric heating element, such as ATTACK TH100, TH102, TH103 or TH107 with a G6/4" thread.

What is the maximum operating pressure and temperature of the tank?

The tank is rated for a maximum operating pressure of 3 bar and a maximum operating temperature of 95 °C, which provides a safe margin above typical heating water operating temperatures of 60-80 °C.

What are the exact dimensions and weight of the tank?

Approximately, the diameter with insulation is approximately 1200 mm, the height approximately 1700 mm, and the weight of the empty tank approximately 150 kg. These are estimated values corresponding to a volume of 1000 l - we recommend verifying the exact dimensions with the seller before installation into confined spaces.

What is the warranty period for the storage tank?

We provide a 24-month warranty from commissioning on ATTACK storage tanks, but no more than 30 months from the date of dispatch from the factory.

Warranty and final recommendation

The manufacturer ATTACK s.r.o. provides a standard warranty of 24 months from commissioning for the ATTACK Storage Tank AK 1000 (insulation included in price), but no more than 30 months from the date of dispatch from the manufacturing plant. To maintain the warranty, we recommend connecting and commissioning the tank in accordance with the installation manual and applicable heating technology standards, using treated heating water and regularly checking the condition of the insulation and the tightness of the connection ports. We are also happy to advise on choosing the right tank volume by phone or email - just provide the type and output of your heat source and we will recommend the most suitable model from the ATTACK range.