Product Overview & Application
The Sunex FISH S2 400 X is a standing solar hot water tank with a nominal capacity of 400 liters for central heating and storage of domestic hot water. Two independent smooth-tube heat exchangers allow the hydraulically separate integration of two heat sources, for example a solar thermal system and a boiler, a wood heating system, a heat pump, or another suitable heat generator.
This version is suitable for bivalent hot water systems with increased storage volume. The storage volume declared for energy labeling is 392 liters.
Technology & Equipment
The drinking water tank is made of steel S235JR and is enameled on the inside. Two magnesium anodes supplement the corrosion protection. The two hydraulically separate smooth-tube heat exchangers are made of steel P235GH in this version.
The lower heat exchanger has a transfer surface of 1.6 m² and achieves a continuous output of 50 kW under defined test conditions. The upper heat exchanger has 1.0 m² of transfer surface and a continuous output of 34 kW. The actually achievable heat transfer depends on temperatures, volume flows, and the hydraulic design of the connected system.
The equipment includes an inspection opening, a circulation connection, several thermometer pockets for temperature sensors, a thermometer connection, and connections for an optional electric heating element. The permanently integrated 50 mm PUR rigid foam insulation reduces heat loss to the installation room. The tank achieves energy efficiency class B with a standby heat loss of 63 W.
Everyday Benefits
The two separate heat exchangers create a flexible basis for systems with regenerative and conventional heat generation. The lower heat exchanger can, for example, absorb solar heat, while the upper heat exchanger takes over reheating via a second heat source.
The inspection opening facilitates inspection, cleaning, and maintenance work on the inside of the tank. Multiple sensor positions support temperature detection and control tailored to the respective system concept.
System integration & compatibility
The Sunex FISH S2 400 X is designed for closed domestic hot water systems with two separately connected heat sources. In addition to solar thermal, suitable boilers, wood heating systems, or heat pumps can be connected. When using a heat pump, the heat exchanger surface area, heat transfer capacity, temperature level, and flow rate must match the intended system.
Connections with 1 1/2 inches are available for the electric auxiliary heating. The electric heating element, safety group, domestic hot water expansion vessel, pumps, controller, and other system components must be selected according to the respective system design.
Technical data at a glance
| Storage tank type |
Hot water storage tank with two heat exchangers |
| Nominal capacity |
400 liters |
| Suitable for drinking water |
Yes |
| Storage tank material |
Steel S235JR, enameled |
| Number of heat exchangers |
2 |
| Insulation |
50 mm rigid polyurethane foam |
| Maximum storage temperature |
95 °C |
| Maximum operating pressure of the storage tank |
10 bar |
| Height |
1,502 mm |
| Width and depth |
757 mm |
| Empty weight |
174 kg |
Installation
The storage tank must be installed exclusively upright in a dry and frost-free room on a level, permanently load-bearing surface. The installation location must be able to safely support the weight of the fully filled storage tank including fittings and piping.
Installation, hydraulic connection, and commissioning may only be carried out by appropriately qualified specialist personnel. Sufficient maintenance clearance must be planned for work on the inspection opening, magnesium anodes, and connection nozzles.
Notes
A safety valve with a response pressure of 6 bar must be installed at the cold water inlet. No shut-off valve may be installed between the safety valve and the storage tank. If the supply pressure exceeds 6 bar, a suitable pressure reducer is also required.
The storage tank must be completely filled with water and vented before the heat exchangers or an optional electric heating element are put into operation. Magnesium anodes, safety valve, tightness, and tank condition must be checked regularly.
Scope of delivery
- Sunex FISH S2 400 X solar hot water storage tank with permanently integrated PUR insulation and gray PVC outer jacket
