Product detailed description

ATTACK Z 200 OKCV - right - horizontal indirect DHW storage tank

The horizontal design of the Z 200 OKCV tank solves situations where a standard vertical cylindrical tank simply cannot be placed - typically in an attic with a sloped roof, a low utility room, a garage, or suspended from the ceiling of a loft. Functionally, it is the same indirect-heated tank as the vertical OKC model, differing only in the orientation of installation and the shape of the internal heat exchanger adapted for the horizontal position.

Why choose the horizontal design and the connection side

The horizontal tank is placed on two feet or suspended on ceiling straps (depending on the supplied mounting kit) and in this position works just as reliably as the vertical model - due to physical stratification, hot water accumulates in the upper part of the cylinder, and the exchanger is positioned to make efficient use of the whole volume of the tank even in the horizontal position.

The choice of the right side determines on which side of the front of the tank the cold and hot water connections and the heating exchanger connections are located - this feature must be carefully checked against the actual location of pipework in the room before ordering, as changing the side after installation is not possible. If in doubt, we recommend consulting your installation company or our technical advisory team.

How an indirect-heated storage tank works

As with the vertical design, domestic hot water is heated indirectly here too - by means of heating water flowing from an external boiler through an internal steel coil (exchanger). The tank itself has no heat source of its own and must always be connected to a functioning boiler, heat pump or other source of heating water. The water intended for consumption is separated from the heating circuit by the wall of the exchanger, so there is no mixing of the two media.

Key features

• Capacity of 200 litres in a horizontal design
• Connections on the: right side (when facing the front of the tank)
• Enamelled steel tank with a magnesium anode
• One heating exchanger shaped for horizontal installation
• Rigid PU insulation with low heat losses
• Designed for placement on feet or suspension on ceiling straps
• Suitable for attics, garages and low utility spaces
• Ready for the addition of an electric heating element via a 6/4" flange
• Same warranty and workmanship quality as the vertical OKC series

Technical parameters

Installation and setup

Before installation it is essential to precisely verify the direction of the connections (right) against the existing DHW and heating pipework - if the opposite side is ordered, the tank cannot be turned around on site without losing the functionality of the feet/straps. The tank is placed horizontally on a stable frame or suspended on certified ceiling straps with sufficient load capacity (the weight of a full 200 l tank is approximately 200 kg of water plus 62.000 kg of steel combined, take this into account when anchoring to the ceiling).

Connection to the boiler is carried out in the same way as with the vertical model - via the exchanger with a circulation pump and priority switching between DHW and heating. Do not forget the DHW safety valve (max. 0.6 MPa), a check valve and, if necessary, a DHW expansion vessel. Installation should be entrusted to a qualified technician authorised to install pressure vessels.

We also recommend verifying the load capacity of the ceiling structure or floor before installation, as a full tank represents a concentrated load at one point in the room.

Maintenance and service life

As with every enamelled tank, we recommend checking the condition of the magnesium anode once a year and replacing it according to wear. Due to the horizontal position, we recommend paying extra attention during servicing to the tightness of the exchanger's flange closure and the condition of the anchoring elements (feet, suspension straps), which should be regularly visually inspected.

Step-by-step commissioning procedure

1. Verify the correct connection side (right) against the pipework design before installation
2. Place the tank on feet or suspend it on certified ceiling straps with sufficient load capacity
3. Connect the exchanger to the boiler's heating circuit with a circulation pump and, if applicable, a three-way valve
4. Connect the cold water supply with a check valve and a DHW safety valve (max. 0.6 MPa)
5. Connect the hot water supply to the points of use
6. Fill and thoroughly vent the tank and the heating circuit
7. Set the required DHW temperature (55-60 °C recommended)
8. Perform a pressure and functional test of the safety valve, check the tightness of the joints
9. Hand over the documentation and instruct the user on operation

Safety warnings

The DHW safety valve with an opening pressure of 0.6 MPa must always be functional and must not be closed off or otherwise taken out of operation; its discharge must freely drain any excess pressure to a sloped drainage area. When suspending from the ceiling, it is essential to verify the load capacity of the structure and use only certified anchoring elements rated for the weight of the full tank including water - underestimating this rule should especially be avoided with the horizontal design. Installation should be entrusted exclusively to a qualified technician.

Operating economics

The operating costs of the Z 200 OKCV - right tank depend on the price of the fuel or energy used by the connected heat source; the tank itself does not consume energy. Quality PU insulation limits heat losses even in the horizontal position, so there is no significant difference in operating costs between the vertical and horizontal designs - the choice of orientation is dictated purely by the layout of the space, not by operating economics.

Who is the Z 200 OKCV - right suitable for

An ideal choice for households and cottages where the utility room has a low ceiling or where the tank needs to be placed in an attic space with sloped walls. 200 litres will cover the typical consumption of a 2-4 member household. Before ordering, always carefully verify the correct connection side (right) according to your project.

How to navigate the ATTACK Z / PZO storage tank range

The ATTACK brand offers several types of hot water storage tanks, which differ in the method of heating and intended use. Below is a brief overview to help you navigate when choosing a related or replacement product:

• Z .. OKC / OKCV ▸ this is the product you are currently viewing - A basic indirect-heated tank with one exchanger, connected to a boiler. The simplest and most affordable solution for DHW preparation if you already have or are planning to install a boiler.
• Z .. OKC ENTR HV 2.2 - Same principle as OKC, plus a built-in 2.2 kW electric heating element - a choice for cottages, summer operation without a boiler, or as backup in case of boiler failure.
• Z .. SOL - Two exchangers - one for the boiler, one large-area exchanger for solar. A choice for households with solar collectors who want to make use of free solar heat as well.
• Z .. HP - One large-area exchanger optimised for the low output temperatures of a heat pump. A choice for households with a heat pump as the main heat source.
• PZO .. PLUS - Directly heated, with its own gas burner, does not need a boiler at all. A choice for cottages, workshops and premises without central heating.

For all indirect-heated variants (OKC, ENTR, SOL, HP), the heating output can be supplemented or backed up with an ATTACK TH electric heating element (outputs 2/2.5/4.5/6 kW) via a 6/4" flange, which is available in our range as a separate product.

Common mistakes when choosing and installing

The most common mistake when ordering horizontal tanks is mixing up the connection side - so always carefully compare the actual layout of pipework in the room with the "right" designation before submitting your order. Other common mistakes include underestimating the load capacity of the ceiling structure when suspending the tank, forgetting the DHW safety valve, and neglecting the annual inspection of the magnesium anode. We also recommend checking in advance whether a tank of these dimensions will actually fit into the planned space, including the working space needed for installation and any future servicing.

Frequently asked questions

How do I know whether I need the right or left version?

Stand facing the tank (the side where the connections will be located) - if the connections should be on the right, order the right version (OKCV); if on the left, order the left version (OKCVL). If in doubt, contact your installation company or our technical advisory team before ordering.

Can the tank be turned around to the other side afterwards?

No, the orientation of the connections is determined by the design of the exchanger and the feet/straps already at the factory and cannot be changed afterwards.

Can I suspend the tank from the ceiling instead of placing it on feet?

Yes, provided certified ceiling suspension straps with sufficient load capacity for the full weight of the tank including water are used. We recommend having the load capacity of the ceiling assessed by a specialist.

Is the heating output the same as with the vertical model?

Yes, the exchanger is designed for the same heating output, only its shape is adapted to the horizontal position of the tank.

What is the maximum DHW pressure the tank can withstand?

The maximum operating pressure of domestic hot water is 0.6 MPa; if the pressure in the water supply network is higher, a pressure reducing valve must be used.

Do I need to check the magnesium anode here as well?

Yes, an annual inspection is recommended just as with vertical tanks; water hardness in the horizontal position does not affect the wear of the anode.

Can an electric heating element be added to the tank?

Yes, the tank has a 6/4" flange ready for fitting an ATTACK TH heating element as a backup heat source.

What load capacity is needed for ceiling mounting?

Take into account the total weight of the full tank - the empty tank weighs approximately 62.000 kg, and once filled with 200 litres of water, the total weight is roughly 200 kg higher.

Can the tank also be used with a solid fuel boiler?

Yes, the exchanger is also suitable for wood or pellet boilers; we recommend adding a thermal safety valve on the heating circuit side against overheating in boilers without their own heat accumulation.

Is the horizontal design more expensive than the vertical one at the same capacity?

The price difference is minimal and mainly results from the different design of the exchanger and feet/straps; functionally and economically, both designs are equivalent.

How is the tank cleaned on the inside?

Through the inspection opening (if included in the design), a visual inspection and removal of any sediment can be carried out; this should be performed by a service technician during a regular inspection.

Is it possible to purchase a vertical version later instead of the horizontal one?

Technically yes, but it is a separate product (e.g. Z 200 OKC), not a modification of the existing horizontal tank - replacement means purchasing a new tank and new installation.

Why do the connections on the horizontal design differ from the vertical OKC model?

The horizontal position requires a different placement of the exchanger and outlets in order to maintain the same heating efficiency and correct use of the whole volume of the tank in this orientation as well.

The effect of insulation on operating costs

The quality and thickness of the tank's thermal insulation directly affects how much energy is consumed just to maintain the set water temperature without any consumption (so-called standby losses). The rigid CFC-free PU foam used in the Z 200 OKCV - right tank has low thermal conductivity and, together with the quality plastic casing, minimises these losses to a reasonable level even during year-round operation, which translates into lower overall costs for domestic hot water preparation compared to older or cheaper tanks with weaker insulation.

Comparison of capacities in the horizontal OKCV range

In addition to the 200-litre capacity, we also offer the horizontal OKCV design in 125 and 160-litre capacities, always with a choice of right or left connection - the appropriate choice of capacity depends on the number of people in the household and the demands of simultaneous consumption (e.g. showering while filling a bathtub at the same time). If you are undecided between two capacities, we recommend choosing the larger of the two, as the additional heat losses are only minimal thanks to the quality insulation, while the comfort of hot water availability increases noticeably.

Summary

The ATTACK Z 200 OKCV - right solves situations where there is nowhere to place a standard vertical tank - an attic, a garage, a low utility room. Functionally, it is just as reliable a solution as the vertical OKC model; the key point is simply to choose the correct connection side (right) according to your project before ordering. Thanks to the long-standing experience of the ATTACK manufacturer in developing DHW storage tanks and its extensive network of service partners in Slovakia and the Czech Republic, this tank represents a safe and proven investment in the hot water comfort of your household.

Warranty and service

The manufacturer ATTACK provides a 5-year warranty on the tank vessel from the date of sale, provided the conditions stated in the warranty certificate are met (regular anode inspection, compliance with maximum operating pressure and temperature, installation of safety equipment in accordance with applicable legislation). A standard warranty period of 24 months applies to the other components of the tank (insulation, casing, electrical components, sensors, accessories). Servicing and spare parts for the entire ATTACK range are provided by a network of authorised service partners in Slovakia and the Czech Republic; our team will be happy to help you choose the right part or find the nearest service centre if needed.