ATTACK OKC 160/1m2 Wall-mounted Tank

Product detailed description

The ATTACK Wall-mounted Cylinder OKC 160/1m2 is an indirectly heated wall-mounted domestic hot water (DHW) cylinder with a capacity of 160 litres and a larger heat exchange surface of 1 m², designed to be mounted on the wall next to a wall-hung or stand-alone ATTACK gas boiler. The cylinder has no heat source of its own - the water is heated indirectly, by means of heating water from the boiler circulating through an internal steel heat exchanger.

The wall-mounted OKC design saves floor space in the boiler room or utility room, as the cylinder hangs on the wall on the same bracket or next to the boiler. It is therefore a suitable choice especially for apartments, smaller houses and spaces where there is not enough room for a stand-alone (free-standing) cylinder.

Key features

• Inner tank made of steel sheet with a high-quality enamelled (glazed) surface resistant to corrosion and limescale build-up
• Magnesium protective anode against electrochemical corrosion of the tank - extends the cylinder's service life and is easily replaceable during a service inspection
• Hardened PUR foam thermal insulation wrapped in an outer casing, minimising heat losses while storing hot water
• Internal steel heating exchanger (coil) with a heat exchange surface of 1.2 m² for indirect heating of water from the boiler
• Suitable for connection to stand-alone ATTACK gas boilers (EKO COMBI, PLQ COMBI, KLQ COMBI, E COMBI, EZ COMBI series) as well as other heat sources with a properly sized exchanger
• Opening / pocket for a thermometer or thermostatic sensor for heating control
• Outlet for an optional electric heating element (purchased separately) for additional water heating outside the heating season, when the boiler is not running
• Drain valve for easy draining and maintenance of the tank
• Robust construction with enamelling tested according to European standards for drinking water tanks
• Manufactured under the ATTACK brand - a proven Slovak manufacturer of heating technology

Type and design

The model designated 160/1m² is equipped with an enlarged heat exchange surface of approximately 1 m² (at a capacity of 160 l), which in practice means a faster water heating response and higher hot water draw-off performance during peak demand (e.g. simultaneous bath filling and showering) compared to the basic Z 160 OKC version with a standard exchanger. It is therefore particularly suitable for households with higher DHW consumption or with a higher-output boiler that can effectively make use of this larger exchanger.

In terms of construction, it is a wall-mounted (hung) cylinder - it is fixed to the wall using a supplied or separately purchased wall bracket, usually in close proximity to the boiler, so that the connecting pipes are as short as possible.

Technical specification

Note: dimensions and weight are approximate estimates based on the capacity and design type of the cylinder; exact values can be found in the manufacturer's technical data sheet or requested when ordering.

How indirect hot water heating works

The ATTACK Wall-mounted Cylinder OKC 160/1m2 is not a heat source - it has no burner or electric heating element of its own (that is only an optional accessory). The heating principle is as follows: heating water heated in the ATTACK gas boiler is pumped by a circulation pump into an internal steel heat exchanger (coil) immersed in the cylinder's tank. Through the wall of the exchanger, it transfers heat to the domestic water filling the internal volume of the 160-litre tank. The domestic water and heating water never physically meet - they are separated by the exchanger wall, so there is no mixing or contamination of drinking water by the heating medium (which may contain corrosion inhibitors and other additives).

Heating is controlled by the boiler's control system in cooperation with a temperature sensor (surface-mounted or immersed in the cylinder's pocket) and usually a three-way switching valve, which redirects the flow of heating water from the radiator circuit to the cylinder's exchanger when DHW is required. As a result, hot water preparation takes priority over space heating, and the household has hot water available practically immediately after the circulation pump starts.

The advantage of this solution over flow heating (a combi boiler without a cylinder) is that the cylinder stores a supply of already heated water - it is therefore possible to draw a larger amount of hot water at once (for example, to fill a bath) without the output limitation that flow heating in a boiler has.

How to choose the right cylinder for your boiler

When choosing the capacity of a cylinder from the Z series (100, 125 or 160 litres), it is recommended to base the decision primarily on the number of people in the household and hot water draw-off habits:

• 100 litres - suitable for 1-3 people, an apartment or smaller family house with standard consumption (showering, kitchen, bathroom without a bath or with occasional bath filling)
• 125 litres - suitable for 3-4 people, a typical family house, combination of shower and bath
• 160 litres - suitable for 4-5 people or more, households with higher demand for simultaneous draw-off (e.g. multiple bathrooms)

This particular model, the ATTACK Wall-mounted Cylinder OKC 160/1m2, has a capacity of 160 litres with a heat exchange surface of 1.2 m². The larger the heat exchange surface, the faster the cylinder can "recharge" the hot water consumed at the same boiler output - when choosing between a standard and an "enlarged" exchanger (where both are manufactured, e.g. the OKC 125/160 series), also consider the output of your boiler: for boilers with higher output (25-30 kW), it is worth choosing the version with a larger exchanger so that its output can actually be used for fast DHW heating.

The cylinder itself does not generate heat - it must be connected to a suitable source, usually a stand-alone ATTACK cast-iron gas boiler (EKO COMBI, PLQ COMBI, KLQ COMBI, E COMBI or EZ COMBI series), which is prepared for connection to an external DHW cylinder via a three-way valve. These boilers only prepare DHW on a flow basis, or not at all, and it is precisely the external cylinder of the Z series that adds the function of hot water storage. When combining with a heat pump or solar system, we recommend choosing specialised models from the HP or SOL series (other products in our range), which have an exchanger sized for lower heat transfer medium temperatures.

Installation and connection

The wall-mounted cylinder is fixed to a load-bearing wall using a supplied or separately purchased mounting bracket, usually in the immediate vicinity of the boiler. The wall must be able to bear the weight of the filled cylinder (empty weight approx. 40 kg + approx. 160 kg of water), so for plasterboard or other non-load-bearing partitions, a suitable fixing system must be used, or the cylinder must be placed on a load-bearing masonry wall.

The cold and hot water connections and the exchanger circuit are connected according to the manufacturer's diagram, usually directly to the boiler or via a distributor. We recommend installing shut-off valves, a safety valve at the cold water inlet, and a check valve. Installation should be entrusted to a qualified plumber/heating engineer, who will also connect the control system (temperature sensor, three-way valve) in cooperation with the boiler's control unit.

Maintenance and service

To ensure the ATTACK Wall-mounted Cylinder OKC 160/1m2 lasts as long as possible, we recommend following a regular service cycle:

• Checking the magnesium anode at least once a year (more often with harder water) - a worn anode must be replaced in time, otherwise it loses its protective function and corrosion of the tank from the inside accelerates
• Desludging/draining the tank via the drain valve once every 1-2 years, especially in areas with harder water, where limescale and sludge settle at the bottom of the tank
• Checking the safety valve on the cold water supply - regularly turn it to verify its function and the patency of the drip pipe
• Checking the tightness of connections and the exchanger at every annual boiler service inspection
• With hard water, consider installing a water softening or dosing device, which significantly extends the service life of both the exchanger and the tank

Regular maintenance is also a condition for warranty recognition in the event of a failure caused by corrosion or limescale deposits.

Safety, standards and legislation

The ATTACK Wall-mounted Cylinder OKC 160/1m2 is a pressure vessel that must be installed and operated in accordance with applicable technical standards and regulations, in particular EN 12897 (indirectly heated storage water heaters) and related pressure equipment regulations. Correct installation always includes a safety valve sized for the cold water inlet, which protects the tank against excessive overpressure during heating - its discharge/drip pipe must be led freely into a space with a slope and must not be closed off or blocked in any way.

We also recommend installing an expansion vessel on the cold water side (especially if there is a check valve or pressure reducing valve on the supply that prevents water from flowing back into the water mains during heating and thermal expansion). Without an expansion vessel, the safety valve may open repeatedly, resulting in unnecessary water loss.

Installation, connection to the boiler's heating circuit and initial commissioning should always be entrusted to a qualified person authorised to install gas and heating equipment. Only professionally performed installation and a regular annual service inspection (together with the boiler inspection) are also a prerequisite for warranty recognition in the event of a claim. The 160-litre cylinder is intended exclusively for heating drinking (domestic) water in the internal distribution systems of buildings, not for other technical purposes.

Position in the ATTACK range

The ATTACK Wall-mounted Cylinder OKC 160/1m2 belongs to the Z series - indirectly heated DHW cylinders from the ATTACK brand, which, in addition to this model, also includes other capacities (100, 125, 160, 200 litres), designs (stand-alone OKH NTR/HV, wall-mounted OKC, horizontal wall-mounted OKCV) and special variants (e.g. with an additional 2.2 kW electric heating element built into the cylinder body, a solar version SOL with two exchangers, or the HP version designed for heat pumps). Thanks to the wide range of variants, it is possible to find a cylinder tailored precisely to the layout of the boiler room and the needs of the household.

We recommend combining this model primarily with stand-alone ATTACK cast-iron gas boilers of the EKO COMBI, PLQ COMBI, KLQ COMBI, E COMBI and EZ COMBI series, which are prepared for connection to an external DHW cylinder, since the boiler itself does not contain a DHW cylinder.

Frequently asked questions

Do I need a boiler in addition to the 160 l cylinder, or does it work on its own?

The ATTACK Wall-mounted Cylinder OKC 160/1m2 is an indirectly heated type - it does not generate heat on its own. It must always be connected to a heat source, most often a stand-alone ATTACK gas boiler prepared for an external DHW cylinder (via a three-way valve), or another suitable source with a sufficiently sized output.

Can the cylinder also be connected to a heat pump or solar collectors?

Yes, in principle it can, however we recommend the specialised HP series (for a heat pump, large-area exchanger for a low-temperature source) or SOL series (with an additional solar exchanger), which are directly designed for these sources. This model from the Z series is primarily intended for a conventional gas boiler.

How long does hot water stay hot in the cylinder without heating?

Thanks to the high-quality PUR insulation, standby losses are low, but the exact time depends on the room temperature and the difference relative to the water temperature. In general, under normal conditions the cylinder maintains a usable water temperature for several hours up to overnight; for longer idle periods without the boiler running, it is advisable to add the optional electric heating element.

Can electric backup heating be purchased additionally?

Yes, the cylinder is prepared (with a pocket/outlet) for an electric heating element with a thermostat, which is purchased separately (e.g. output of 2-6 kW depending on the model). This allows DHW heating even outside the heating season, when the boiler is switched off.

What is the warranty on the cylinder?

We provide a 5-year warranty on the insulated tank, and 24 months on other parts (e.g. anode, gaskets, accessories) from the date of dispatch, provided the installation conditions and regular maintenance (especially anode inspection and replacement) are observed.

How often does the magnesium anode need to be replaced?

We recommend checking the anode at least once a year during the boiler's service inspection. With more aggressive or harder water, more frequent checks and earlier replacement may be necessary - a worn anode loses its anti-corrosion function.

What is the difference between the 100, 125 and 160 litre capacities?

The difference is mainly in capacity - a larger volume means more accumulated hot water available at once (e.g. when filling a bath while showering simultaneously), but also larger physical dimensions and weight. The choice depends on the number of people in the household and water draw-off habits.

Can a standard wall bear the weight of the filled cylinder?

A filled cylinder weighs a total (empty weight + 160 l of water) of roughly 200 kg, so it must be anchored to a load-bearing masonry wall with suitable anchors, or a separate stand must be used. On thin non-load-bearing partitions (e.g. plasterboard), the wall-mounted cylinder must not be installed without additional reinforcement.

Warranty and service

For ATTACK brand products, we provide a 5-year warranty on the insulated tank of the cylinder (subject to compliance with installation conditions and regular maintenance, including inspection and replacement of the magnesium anode) and 24 months on other parts and accessories from the date of dispatch from production. Service and spare parts (e.g. anodes, gaskets, accessories) are available in Slovakia. If you have any questions about selection, installation or warranty claims, please do not hesitate to contact us - we will be happy to help with choosing a suitable boiler or control system for this cylinder as well.