Plate Heat Exchangers

The combi boiler plate heat exchanger (DHW plate exchanger) is the part that transfers the heat of the hot water in the central heating circuit to the domestic hot water flowing from the tap. When the plates scale up, the hot water heats slowly or comes out lukewarm. When a leak develops between the plates, domestic water passes into the heating circuit and the boiler pressure rises by itself. This category contains plate heat exchangers compatible with Baymak, Demirdöküm, ECA, Bosch, Buderus, Vaillant, Viessmann, Ariston, Airfel, Alarko and Immergas combi boilers, together with heat exchanger gaskets.

Three Measurements for the Right Heat Exchanger

1. Number of plates: Models with 12, 14, 16, 20 and 24 plates are available. Verify by counting the plates on the removed heat exchanger.
2. Screw spacing (pin spacing): This is the distance between the connection holes (e.g. 142, 148, 154, 156.5, 160, 166 mm). Since the same number of plates can come with different screw spacings, the measurement must always be checked.
3. Connection type: Flat type, 4-lug screw-on, or body with 1/2" – 3/4" male threaded fittings.

Plate Heat Exchangers by Combi Boiler Brand

• Vaillant: Vaillant Turbotec 16 plates and Turbotec / Ecotec compatible 4-lug screw-on 12 plates
• Bosch, Buderus, Viessmann, ECA: 14 plates, 154 mm 16 plates (including Alarko Serena), Zilmet 17B1901206, 12 plates and Zilmet 17B1901426, 14 plates, 148 mm
• Ariston: Clas, Matis, Genus, Egis 16 plates and 142 mm 12 plates (Egis-II, Clas, Genus Evo)
• Demirdöküm: Milenyum Plus and Zilmet 17B2071206, 166 mm 12 plates
• Baymak, Baxi, Airfel, Ideal: flat type 12 plates, 156.5 mm, Zilmet 17B1901230, 160 mm and Ideal Logic / Airfel 20 plates, 160 mm
• Alarko, Ferroli (threaded fittings): 190 mm 16 plates and 207 mm 14 plates
• Immergas: 152 mm 14 plates

If you cannot see your boiler model in the list, count the plates and measure the screw spacing of the removed heat exchanger and compare them with the values on the product pages.

Heat Exchanger Gasket and O-Ring

When replacing the heat exchanger, the old gaskets should not be reused, because a hardened gasket will leak after the replacement. The Baymak, Baxi Luna, Ariston Clas compatible o-ring, Vaillant Turbotec o-ring (25×19×6 mm), Viessmann WH1C / WH1A o-ring (25×15×8 mm) and Bosch compatible large and small gasket set are in this category.

The plate heat exchanger should not be confused with the boiler's main heat exchanger. The main heat exchanger is the primary exchanger above the burner that heats the central heating water. The Bosch Buderus GB012 main heat exchanger (recuperator) is also in this category.