Plate heat exchanger Viessmann 7817554

Primary (main) heat exchanger Viessmann 7817554. It is designed to heat the coolant in the heating system and is installed in Viessmann gas boilers with power 24 kW with open combustion chamber (atmospheric). Technical specifications: Part numbers: 7817554, 956.781.002. Manufacturer: Viessmann (Germany). Heat exchanger type: Primary (main), monotermic. Material: High-quality copper with anti-corrosion silicone-aluminum coating. Number of plates: 80 lamellas (loops). Compatibility (most likely): Viessmann Vitopend 100 boilers (models WH0A, WHO, WHEA) with power 24 kW, atmospheric versions. Gross weight: 6.2 kg. Compatibility features: When selecting a Viessmann heat exchanger, it is very important not to confuse different modifications that may look identical externally. Key points: This heat exchanger 7817554 is intended for atmospheric (flue) Vitopend 100 boilers. They have an open combustion chamber, and flue gas removal occurs naturally (due to draft in the chimney). For turbocharged (with closed combustion chamber) boilers (Vitopend 100 models with turbocharging), a different heat exchanger is used — with part number 7817484. This is also indicated by different types of connection pipes: for 7817554 — combined (threaded + clip connections), for the turbo version — different. Therefore, be sure to check your boiler: if it has a closed combustion chamber and is connected to a coaxial chimney (pipe in pipe), then you most likely need heat exchanger 7817484, not this one. ⚙️ When replacement is needed: Replacement is required for the following signs of malfunction: Pressure drop: System pressure drops, although no visible leaks. Efficiency decrease: Radiators heat significantly worse with normal burner operation. Overheating and noises: Boiler is noisy.