uniSTOR plus VIH RW 500

Product detailed description

Vaillant uniSTOR plus VIH RW 500 hot water storage tank

Vaillant uniSTOR plus VIH RW 500 is the largest model in the uniSTOR plus range with a single heat exchanger, designed for use with a heat pump as the sole heat source. With a volume of 460 liters, it is a solution for larger households, multi-generational homes or buildings with high and uneven demand for hot water – for example, houses with three or more bathrooms, larger guesthouses or facilities with high hot water consumption in a short time.

It is structurally similar to the RW 400 model and shares the same diameter (790 mm), differing mainly in the height of the tank, which at a volume of 460 liters reaches 1802 mm. The inner tank is made of steel with a high-quality enamelled surface on the potable water side and is equipped with a magnesium protective anode that provides active cathodic protection against corrosion throughout the product's lifetime.

Technical specifications of VIH RW 500

• Tank volume: 460 liters
• Tank height (with casing): 1802 mm
• Width (with casing): 790 mm
• Depth (with casing): 900 mm
• Empty tank weight (without water): approximately 235 kg
• Operating weight of the filled tank: approximately 694 kg
• Maximum operating pressure (domestic water): 10 bar
• Maximum operating pressure (heating circuit): 10 bar
• Maximum hot water temperature: 85 °C
• Integrated magnesium protective anode against corrosion
• Enamelled inner tank surface
• One heating heat exchanger with a smooth tube for connection to a heat pump

Construction and thermal insulation

The RW 500 tank casing is insulated with rigid PU foam with high density applied directly to the steel tank, ensuring minimal heat loss even with a large water volume. Due to the largest volume in the uniSTOR plus range, high-quality insulation is especially important for the RW 500 model – an improperly insulated tank would result in significantly higher absolute heat losses in kWh compared to smaller models. The high weight of the filled tank (694 kg) requires attention during installation planning, especially if placed outside the ground floor.

The volume of 460 liters represents a significant reserve of hot water, which can cover periods of increased consumption, for example during visits from multiple guests or in facilities with operational characteristics (small guesthouses, common areas in apartment buildings). Despite the large volume, the tank maintains the same diameter of 790 mm as the RW 400 model, making it easier to fit into technical rooms designed for the smaller model.

Installation and connection

The tank is installed as a free-standing unit on adjustable feet, which allow precise leveling on an uneven floor. Due to the height of 1802 mm, it is necessary to allow for a minimum room height of 2000 mm. Connections for cold and hot water, circulation and the heating circuit are solved by standard threaded connections at the top of the tank.

Due to the high weight of the filled tank (694 kg), we strongly recommend verifying the floor load capacity before installation, especially when installing outside the ground floor or in older buildings. The tank is compatible with Vaillant heat pump controls (senzoCOMFORT, multiMATIC), including setting the priority of hot water heating, time programs and the legionella protection cycle, which is especially important for maintaining water hygiene in larger volumes.

Compatible accessories

The VIH RW 500 tank can be supplemented with a connection kit with a safety valve for the domestic water side, an expansion vessel for hot water with sufficient capacity corresponding to the large tank volume, insulation sleeves for the connecting pipes and a temperature sensor compatible with the heat pump control unit. In buildings with multiple draw-off points, we also recommend a circulation pump with time or temperature control.

For whom is the RW 500 model suitable

The RW 500 model is intended for larger households with 5 or more members, multi-generational homes, houses with three or more bathrooms or for small businesses with higher and peak demand for hot water. Thanks to the volume of 460 liters, it provides the largest reserve in the entire uniSTOR plus range with a single heat exchanger.

Frequently asked questions (FAQ)

How much space do I need to install the RW 500 tank?
We recommend a minimum floor space of 100 × 100 cm and a minimum room height of 2000 mm, as the tank has a height of 1802 mm.

Will a standard floor support the weight of 694 kg of a filled tank?
In masonry buildings with a concrete floor, this is usually not a problem, but due to the high weight, we recommend always checking the floor load capacity with a structural engineer, especially outside the ground floor.

Is the RW 500 model suitable for an apartment building?
For shared hot water preparation in a smaller apartment building or a multi-generational home, the RW 500 can be a suitable solution, but the overall daily consumption and heat pump performance must be individually assessed.

What is the difference between RW 400 and RW 500?
Both models have the same diameter of 790 mm, the RW 500 model is taller (1802 mm compared to 1502 mm) and offers a larger volume (460 l compared to 375 l) by 85 liters.

How often should the magnesium anode be checked on such a large tank?
We recommend a visual inspection once a year, more frequently in areas with hard water, as the large water volume means more contact with the anode.

Operation with a heat pump

For the RW 500 model, it is especially important to correctly dimension the heat pump power in relation to the large water volume that needs to be heated. Heat pumps work most efficiently at lower output temperatures (35 – 55 °C), so for a large tank volume we recommend consulting with a designer who will take into account the actual time needed to heat the entire volume and set an optimal hot water preparation time program, for example during night hours with a more favorable electricity rate.

Maintenance and service

Maintenance of the RW 500 tank includes regular inspection of the magnesium anode, checking the function of the safety valve on the domestic water side and occasional descaling of the tank. Due to the large water volume, we recommend performing service at least once a year, ideally as part of a regular heat pump service check. Access to the inspection hatch and anode is from the front side of the casing.

Operational safety

The tank is dimensioned for a maximum operating pressure of 10 bar. With a volume of 460 liters, it is essential to use an adequately dimensioned expansion vessel on the hot water side, as the volume of thermal expansion of water when heated is significantly higher than with smaller models. A certified safety valve with an opening pressure according to current regulations is a mandatory part of every installation.

Comparison within the uniSTOR plus range

The RW 500 model closes the uniSTOR plus range with a single heat exchanger as its largest representative, following the RW 250, RW 300 and RW 400 models. For households or businesses that do not need such a high volume, any of the smaller models are available with the same quality of processing and technology. On the other hand, if you plan to combine a heat pump with another heat source, for example solar collectors, we recommend considering the bivalent model uniSTOR plus VIH SW with two heat exchangers instead of increasing the volume of the single heat exchanger RW model.

Economic and ecological benefits

For larger households or businesses with high demand for hot water, a centralized large-volume tank in combination with a heat pump is a significantly more efficient solution than multiple smaller local heaters. The high volume of 460 liters allows heating to be concentrated during periods with the most favorable electricity prices (for example, night tariff) and subsequently covering peak demand during the day without the need for additional heating, which reduces the required heat pump capacity and at the same time increases user comfort.