ATTACK AK 3000 Storage Tank (insulation included in price)

Product detailed description

Why a buffer tank determines heating efficiency

ATTACK Buffer Tank AK 3000 (insulation included in price) is a steel accumulation (buffer) tank with a volume of 3000 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 for storing heating water - heating of domestic hot water (DHW) with this type of tank is solved externally, for example through a storage water heater or a flow module.

The biggest benefit of a buffer tank can be seen when combined with a solid fuel gasification boiler, such as the ATTACK DPX or ATTACK SLX. These boilers achieve the highest efficiency and cleanest combustion precisely when they burn at full, rated output - that is, when they burn a full load of wood "in one go" without throttling the air supply. Without a buffer tank, the boiler would often have to operate in a choked mode (to avoid overheating the system), which leads to worse combustion, higher tar formation, and shorter boiler and chimney lifespan. With the ATTACK Buffer Tank AK 3000 (insulation included in price), the boiler burns the fuel at full output at once and the surplus heat is stored in the water reserve in the tank - from there, the heating system gradually draws it as needed by the household, even several hours after the boiler has burned out.

The same principle also works with an electric boiler or heat pump: the 3000 l tank allows the heat source to operate in longer, less frequent cycles instead of constantly switching on and off for short intervals, which extends the lifespan of the compressor/heating elements and reduces energy consumption. This is a large-volume industrial/commercial buffer tank, designed for larger boiler rooms, agricultural operations, dryers, guesthouses or apartment buildings with a central heat source, where heat from multiple boilers or from a high-capacity gasification boiler needs to be stored for a longer period.

Key features of the AK3000K tank

• Volume of 3000 litres - designed so that, with the recommended heat source output of 120 - 150 kW, it provides a sufficient heat reserve between heating cycles.
• Soft, removable polyester insulation 100 mm thick - significantly reduces heat loss to the surroundings during long-term storage of hot water, while being easy to unfasten for inspection or servicing of the tank and its fittings.
• Outer cover of the insulation made of leatherette (PVC fabric) in silver-grey - resistant to abrasion and easy to maintain, visually blending into the boiler room interior rather than looking like a "technical" element.
• 6 connection fittings distributed around the shell and on the top/bottom side of the tank, allowing connection of the heat source, heating circuits, an additional electric heating element (backup heating), venting, draining and temperature sensors.
• Steel shell with a corrosion-resistant internal surface treatment, designed for a maximum operating pressure of 3 bar and a maximum temperature of 95 °C - a safe margin compared to typical operating temperatures of heating water (60-80 °C).
• Suitable for vertical position thanks to feet/a stand, which at this volume facilitates precise temperature layering (stratification) - warmer water naturally stays at the top, cooler water at the bottom, increasing the usable amount of 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 fittings - suitable as a backup or supplementary heat source outside the heating season or in case of failure of the main source.
• Without a built-in heat exchanger - the tank is designed purely for accumulating heating water; if you also need to prepare DHW via a built-in heat exchanger, check out 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; before installation (e.g. in case of limited space in the boiler room or narrow doors/staircase), we recommend verifying the exact dimensions directly with the seller before ordering.

How to choose the right buffer tank volume correctly

The most common recommended rule when selecting a buffer tank for a solid fuel gasification boiler is: allow approximately 20 to 25 litres of buffer volume for each 1 kW of rated boiler output. 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. With a tank volume of 3000 litres, this means it is suitable for a heat source with an output of approximately 120 to 150 kW.

If you have, for example, a wood gasification boiler with an output in this range (from the ATTACK range, these are for example some models from the DPX or SLX series - both Standard and Profi versions), the tank ATTACK Buffer Tank AK 3000 (insulation included in price) is appropriately sized for your system. For a 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 possibly connecting multiple tanks in a cascade - so that the buffer volume matches the sum of the outputs of the connected sources.

With a volume of 3000 l, it also holds true that the larger the tank, the longer it can supply 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 from a single boiler load and one buffer 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 greater portion of the stored heat to be used than high-temperature radiator systems).

It is also worth remembering that a buffer tank is worthwhile 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 backup heating options

The ATTACK Buffer Tank AK 3000 (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 fittings, while the heating system draws heat via another pair, hydraulically separating both circuits so the system operates more stably even with fluctuating flow on the source side. The remaining fittings (a total of 6 on this tank) are used, for example, for installing a temperature sensor, air vent valve, safety valve, or for connecting an additional electric heating element.

The option to install an electric heating element is a practical solution for periods when you do not want to heat with solid fuel (e.g. outside the main heating season) or as a backup in case of failure of the main source. 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 fittings of this buffer tank. We recommend choosing the element's output based on the tank volume and the required heating-up speed.

When installing the ATTACK Buffer Tank AK 3000 (insulation included in price), make sure there is sufficient manoeuvring space in the boiler room - given a diameter with insulation of approximately 1600 mm and a height of approximately 2450 mm (both values are approximate, see above), it is necessary to check in advance the clearance 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 fittings, to ensure comfortable access for servicing, gasket replacement or checking/topping up 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 internal walls and shortens the lifespan of the whole system, including the boiler and circulation pumps.

Connection with other heating system components

The ATTACK Buffer Tank AK 3000 (insulation included in price) forms only one link in the heating chain. Customers most often combine it with the wood gasification boiler ATTACK DPX or ATTACK SLX (Standard and Profi versions, output range approximately 15-35 kW), with the boiler's output matching the recommended range of 120-150 kW mentioned above. When combined with a heat pump or electric boiler, the tank serves as a hydraulic separator and heat store 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 supplementing the system with a separate DHW storage water heater (e.g. from the ATTACK Z range - Z100, Z125, Z160, Z200 and others, available in our range), or choosing one of the models from the AS/HR/HRS/TUV/TUVS range instead of this tank, which have a heat exchanger built directly into the tank.

Maintenance and inspection of the tank during operation

The ATTACK Buffer Tank AK 3000 (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 fittings, the condition of the air vent valve and the heating circuit safety valve, 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 moving or handling in the boiler room), we recommend repairing the damaged spot in time 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 with drinking water - the risk of limescale buildup is thus significantly lower than with DHW storage tanks, but we still recommend visually inspecting the inside of the tank through the inspection opening (if the model has one) once every few years (for example during a system shutdown), or at least monitoring the quality and colour of the heating water when desludging the system. Cloudy or rusty water may indicate the need for water treatment or a check for 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 internal surface from corrosion caused by exposure to air. If you plan to take the tank completely out of operation for a longer period, consult a qualified installer about the appropriate preservation procedure.

Frequently Asked Questions

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

No, this AK3000K 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 the same tank, choose from our AS, HR, HRS, TUV or TUVS range.

How big a boiler can I connect to this tank?

For a volume of 3000 litres, we recommend a heat source with an output of approximately 120 to 150 kW, according to the rule of 20-25 litres of accumulation per 1 kW of output. For a more powerful source, it is preferable to choose a larger volume or connect multiple tanks in a cascade.

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

Yes, the AK3000K buffer 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 the 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 with an outer cover made of leatherette in silver-grey.

Can I install an electric heating element for backup heating into the tank?

Yes, the tank has 6 connection fittings, one of which can be used to install an electric heating element, for example 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 designed for a maximum operating pressure of 3 bar and a maximum operating temperature of 95 °C, which provides a safe margin compared to typical operating temperatures of heating water of 60-80 °C.

What are the exact dimensions and weight of the tank?

Approximately, the diameter with insulation is about 1600 mm, the height is about 2450 mm and the weight of the empty tank is about 250 kg. These are estimated values corresponding to a volume of 3000 l - we recommend checking the exact dimensions with the seller before installation in confined spaces.

What is the warranty period on the buffer tank?

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

Warranty and final recommendation

For the ATTACK Buffer Tank AK 3000 (insulation included in price), the manufacturer ATTACK s.r.o. provides a standard warranty of 24 months from commissioning, 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 fittings. When choosing the right tank volume, we are happy to advise by phone or e-mail - just provide the type and output of your heat source and we will recommend the most suitable model from the ATTACK range.