ATTACK AK 200 Storage Tank (insulation included in price)

Product detailed description

Why a buffer tank is key to heating efficiency

ATTACK Buffer Tank AK 200 (insulation included) is a steel accumulation (buffer) tank with a volume of 200 litres, designed for storing hot heating water from any heat source - a wood gasification boiler, heat pump, electric boiler, gas boiler or solar collectors. This 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 handled externally, for example via a storage water heater or flow-through 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 throttled mode (to avoid overheating the system), which leads to worse combustion, increased tar formation and shorter boiler and chimney life. With the ATTACK Buffer Tank AK 200 (insulation included), the boiler burns the fuel at full output at once, and the excess heat is stored in the water supply in the tank - from where the heating system gradually draws it according to the household's current need, even several hours after the boiler has burned out.

The same principle also applies to an electric boiler or heat pump: a 200 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 service life of the compressor/heating elements and reduces energy consumption. This is a typical volume for an average family house heated by an ATTACK DPX or SLX wood gasification boiler - a tank of this size can hold the heat from one or more boiler loads and gradually release it into the heating system over the following days, significantly reducing the number of boiler starts and stops.

Key features of the AK200K tank

• Volume of 200 litres - designed to provide a sufficient heat reserve between heating cycles at a recommended heat source output of 8 - 10 kW.
• Soft, removable polyester insulation 100 mm thick - significantly reduces heat losses to the surroundings during long-term storage of hot water, while being easy to unfasten for inspection or servicing of the tank and connections.
• Leatherette (PVC fabric) outer insulation cover in silver-grey - resistant to abrasion and easy to maintain, visually blends into the boiler room interior rather than looking like a "technical" element.
• 5 connection ports distributed around the shell and on the top/bottom of the tank, allowing connection of the heat source, heating circuits, an auxiliary electric heating element (backup heating), air 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 above typical heating water operating temperatures (60-80 °C).
• Suitable for vertical installation thanks to feet/a base, which, at this volume, makes precise temperature stratification easier - warmer water naturally stays at the top, cooler water at the bottom, increasing the usable proportion of accumulated heat.
• Option to additionally install an electric heating element (e.g. ATTACK TH100, TH102, TH103 or TH107) directly into one of the tank's ports - suitable as a backup or supplementary heat source outside the heating season or in case of main heat source failure.
• No built-in heat exchanger - the tank is intended purely for heating water accumulation; if you also need DHW preparation via a built-in heat exchanger, check our range of AS/HR/HRS/TUV/TUVS tanks with a 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 with the seller before ordering, especially before installation (e.g. in case of limited boiler room space or narrow doors/staircases).

How to correctly choose the volume of a buffer tank

The most commonly recommended rule when choosing a buffer tank for a solid fuel gasification boiler is: allow approximately 20 to 25 litres of buffer volume per 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 consumes it. For a tank with a volume of 200 litres, this means it is suitable for a heat source with an output of approximately 8 to 10 kW.

If, for example, you have a wood gasification boiler with an output in this range (from ATTACK's range, this includes some models from the DPX or SLX series - both Standard and Profi versions), the ATTACK Buffer Tank AK 200 (insulation included) is appropriately sized for your system. For a higher-output boiler, or if you plan to combine several 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 buffer volume matches the combined output of the connected sources.

For a 200 l volume, it also holds true that the larger the tank, the longer it can continue supplying heat even after the boiler has completely burned out - in a well-designed, 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 outside temperature, the house's heat losses and the heating system's temperature gradient (lower temperatures, e.g. with underfloor heating, allow a larger 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 service life of the compressor, circulation pumps and electronics.

Connection, installation and additional heating options

The ATTACK Buffer Tank AK 200 (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 via one pair of ports, while the heating system draws heat via the other pair, hydraulically separating both circuits and allowing the system to operate more stably even with fluctuating flow on the source side. The remaining ports (there are 5 in total on this tank) can be used, for example, for a temperature sensor, air vent valve, safety valve, or connection of an auxiliary electric heating element.

The option to install 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 main heat source failure. Our range includes the 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 this buffer tank's ports. We recommend choosing the element's output based on the tank's volume and the desired heating-up speed.

When installing the ATTACK Buffer Tank AK 200 (insulation included), allow for sufficient handling space in the boiler room - given a diameter with insulation of approximately 750 mm and a height of approximately 1050 mm (both values approximate, see above), you should check in advance that the tank will fit through 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 sensor checks/additions.

We recommend filling the tank only with treated heating water in accordance with applicable standards (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 service life of the entire system, including the boiler and circulation pumps.

Connection with other heating system components

The ATTACK Buffer Tank AK 200 (insulation included) is just 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 ranges of approximately 15-35 kW), with the boiler's output matching the recommended range of 8-10 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 adding a separate DHW storage water heater to the system (e.g. from the ATTACK Z series - 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 Buffer Tank AK 200 (insulation included) requires minimal but regular maintenance. We recommend checking once a year (e.g. before the start of the heating season) the tightness of all 5 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 silver-grey leatherette covering is resistant to normal abrasion, but in case of mechanical damage (e.g. during transport or handling in the boiler room), we recommend repairing the damaged area promptly to prevent 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 therefore significantly lower than with DHW storage tanks, but we still recommend visually inspecting the inside of the tank once every few years (e.g. during a system shutdown) via an inspection 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 the need for water treatment or a check for corrosion in the system.

During a long-term shutdown (e.g. outside the heating season), there is no need to drain the tank - on the contrary, leaving water in the system protects the internal surface from corrosion caused by air exposure. 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 also need to buy a heat exchanger for this tank?

No, this AK200K model cannot be retrofitted with a built-in heat exchanger - it serves purely for heating water accumulation. If you need DHW preparation via a heat exchanger in a single tank, choose from our AS, HR, HRS, TUV or TUVS series.

How big a boiler can I connect to this tank?

For a 200-litre volume, we recommend a heat source with an output of approximately 8 to 10 kW, following the rule of 20-25 litres of buffer volume 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 AK200K 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 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 leatherette cover in silver-grey.

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

Yes, the tank has 5 connection ports, one of which can be used to install an electric heating element, such as the 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, providing 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 around 750 mm, the height around 1050 mm, and the weight of the empty tank around 45 kg. These are estimated values corresponding to a 200 l volume - we recommend verifying the exact dimensions with the seller before installation in tight spaces.

What is the warranty period for 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 shipment from the factory.

Warranty and final recommendation

The ATTACK Buffer Tank AK 200 (insulation included) is covered by the manufacturer ATTACK s.r.o. with a standard warranty of 24 months from commissioning, but no more than 30 months from the date of shipment from the factory. 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.