ATTACK AK 1500 Storage Tank (insulation included in price)

Product detailed description

Why a buffer tank determines heating efficiency

ATTACK Storage Tank AK 1500 (insulation included) is a steel buffer (storage, accumulation) tank with a volume of 1500 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 - domestic hot water (DHW) preparation with this type of tank is handled externally, for example through a storage water heater or a flow module.

The greatest benefit of a buffer tank is 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 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 buffer tank, the boiler would often have to operate in a choked mode (to avoid overheating the system), which leads to poorer combustion, higher tar formation and shorter boiler and chimney life. With the ATTACK Storage Tank AK 1500 (insulation included), the boiler burns the fuel at full output in one cycle and the excess heat is stored in the water reserve in the tank - from there, the heating system gradually draws it according to the current needs of the household, even several hours after the boiler has burned out.

The same principle also works with an electric boiler or heat pump: the 1500 l tank allows the heat source to work 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, intended for larger boiler rooms, agricultural operations, drying facilities, guesthouses or apartment buildings with a central heat source, where heat from multiple boilers or from a high-capacity gasification boiler needs to be accumulated for a longer period.

Key features of the AK1500K tank

• 1500 litre volume - designed to provide a sufficient heat reserve between individual heating cycles at a recommended heat source output of 60 - 75 kW.
• Soft, removable polyester insulation 100 mm thick - significantly reduces heat losses into the surroundings during long-term storage of hot water, while being easy to unfasten for inspection or servicing of the tank and fittings.
• Outer insulation cover made of leatherette (PVC fabric) in a silver-grey finish - resistant to abrasion and easy to maintain, visually blending in as part of the boiler room interior rather than 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, supplementary electric heating element (booster heating), venting, draining and temperature sensors.
• Steel shell with a corrosion-resistant internal surface treatment, rated for a max. operating pressure of 3 bar and max. temperature of 95 °C - a safe margin above typical operating temperatures of heating water (60-80 °C).
• Suitable for vertical installation thanks to feet/a base, which at this volume facilitates precise temperature layering (stratification) - warmer water naturally stays at the top, cooler water at the bottom, increasing the usability of the accumulated heat.
• Option of additionally installing an electric heating element (e.g. ATTACK TH100, TH102, TH103 or TH107) directly into one of the tank ports - suitable as a backup or supplementary heat source outside the heating season or in case of a main heat source failure.
• No built-in heat exchanger - the tank is designed purely for accumulating heating water; 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 case of a limited boiler room space or narrow doors/staircase) directly with the seller before ordering.

How to correctly choose the volume of a buffer tank

The most common recommended rule when selecting a buffer tank for a solid fuel gasification boiler is: allow approximately 20 to 25 litres of storage volume for every 1 kW of rated boiler output. This rule is based on the fact that a 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 uses it. For a tank with a volume of 1500 litres, this means it is suitable for a heat source with an output of approximately 60 to 75 kW.

If you have, for example, a wood gasification boiler with 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 ATTACK Storage Tank AK 1500 (insulation included) 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 several tanks in a cascade - so that the storage volume matches the sum of the outputs of the connected sources.

At a volume of 1500 l, it also applies 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 loading and a single 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 larger portion of the stored heat to be used than high-temperature radiator systems).

It should also be remembered that a buffer 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 additional heating options

The ATTACK Storage Tank AK 1500 (insulation included) 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 through one pair of ports, while the heating system draws heat through 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, an air vent valve, a safety valve, or for connecting a supplementary electric heating element.

The option of fitting 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 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 a G6/4" thread - compatible with the ports of this buffer tank. We recommend choosing the element's output to match the tank volume and the desired heating speed.

When installing the ATTACK Storage Tank AK 1500 (insulation included), allow for sufficient handling space in the boiler room - given a diameter with insulation of approximately 1300 mm and a height of approximately 2050 mm (both values approximate, see above), it is necessary to check 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 comfortable access during 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. 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 whole system, including the boiler and circulation pumps.

Connection with other heating system components

The ATTACK Storage Tank AK 1500 (insulation included) is only one link in the heating chain. Customers most often combine it with the ATTACK DPX or ATTACK SLX wood gasification boiler (both Standard and Profi versions, output range approximately 15-35 kW), with the boiler output matching the recommended 60-75 kW range mentioned above. When combined with a heat pump or electric boiler, the tank serves as a hydraulic separator and heat reservoir, 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 AS/HR/HRS/TUV/TUVS models instead of this tank, which have a heat exchanger built directly into the tank.

Maintenance and inspection of the tank during operation

The ATTACK Storage Tank AK 1500 (insulation included) 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 valve and the heating circuit's safety valve, as well as the overall condition of the outer insulation cover - the leatherette covering in silver-grey is resistant to normal wear, but in case of mechanical damage (e.g. during transport or handling in the boiler room), we recommend repairing the damaged area promptly to avoid unnecessary heat losses.

Since this is a tank without a built-in heat exchanger, the interior of the tank only comes into contact with treated heating water, not drinking water - the risk of limescale buildup is thus significantly lower than with DHW cylinders, but we still recommend visually inspecting the interior of the tank once every few years (for example, during a system shutdown) through an inspection opening, if the model is equipped with one, 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 corrosion check in the system.

During a long-term shutdown (e.g. outside the heating season), it is not necessary to drain the tank - on the contrary, leaving the 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 AK1500K model cannot be additionally fitted with a built-in heat exchanger - it serves purely for accumulating heating water. If you need both heating water storage and domestic hot water preparation via a heat exchanger in one tank, choose from our AS, HR, HRS, TUV or TUVS range.

How large a boiler can I connect to this tank?

For a volume of 1500 litres, we recommend a heat source with an output of approximately 60 to 75 kW, according to the rule of 20-25 litres of storage per 1 kW of output. For a more powerful source, it is more appropriate 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 AK1500K 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 evens out 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 a silver-grey finish.

Can I fit an electric heating element into the tank for additional heating?

Yes, the tank has 6 connection ports, 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 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 1300 mm, the height is approximately 2050 mm and the weight of the empty tank is approximately 190 kg. These are estimated values corresponding to a volume of 1500 l - we recommend verifying the exact dimensions with the seller before installation in confined spaces.

What is the warranty period for the buffer tank?

We provide a 24-month warranty from commissioning for ATTACK buffer tanks, but no more than 30 months from the date of shipment 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 1500 (insulation included), but no more than 30 months from the date of shipment 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 happy to advise on choosing the correct tank volume by phone or e-mail - just let us know the type and output of your heat source and we will recommend the most suitable model from the ATTACK range.