Zilmet Combi Boiler Plate Heat Exchanger 16 Plates – 17B1901601, 148 mm, 28 kW | Beretta R8037, Riello 4364201, Arçelik Compatible

Zilmet ZB 190 body 16-plate domestic hot water (sanitary) heat exchanger. It is the part of a combi boiler that transfers the heat of the hot water in the heating circuit to the mains water without mixing. In Beretta exploded diagrams it appears as pos. 1 – Scambiatore sanitario and is used in 28 kW class appliances.

Zilmet code 17B1901601, Beretta spare part code R8037, Riello equivalent 4364201. Made in Italy, plates made of AISI 316L stainless steel, copper brazed.

🚨 Before Ordering: Collared Port Distinction

The Zilmet ZB 190 body with 16 plates + 148 mm pin spacing comes in two separate codes, and they are not interchangeable:

Both have the same body, the same number of plates and the same pin spacing; the difference is the collar on the port. If the ports of the part you removed have no collar, this product will not fit. Compare the port shape in the photos with the part in your hand.

Dimensions

🪤 148 mm and 154 mm are two different dimensions of the same part, not two different products: 148 mm is the distance between the mounting pins, while 154 mm is the distance between the centers of the water ports. In Turkey this heat exchanger is searched for as 148 mm.

The Number of Plates Determines the Boiler Output

Beretta exploded diagrams show two versions of the same body:

• 12 plates (R8036) → 24 kW appliances
• 16 plates (R8037) → 28 kW appliances ← this product

Both fit the same seat. If a 12-plate unit is fitted to a 28 kW appliance, the heat transfer surface is insufficient: the domestic hot water flow rate drops, and when the tap is fully open the water does not reach the desired temperature. Confirm the kW rating of the appliance when ordering.

Compatible Models

🪤 Note on Riello: Some Riello models use a heat exchanger with threaded (screw-in) ports, not the collared o-ring port of this product. On Riello appliances, check the port type of the part you removed.

For Arçelik and Beko combi boilers, the decision is made by comparing the pin spacing (148 mm), the number of plates (16) and the collared port type.

When Should It Be Replaced?

• The radiators heat up, but domestic hot water does not come or flows lukewarm. The most typical symptom — the domestic water side of the heat exchanger is clogged with limescale.
• The water runs alternately hot and cold. The passage cross-section between the plates has narrowed and heat transfer has become unbalanced.
• Pressure drops on the heating side and water escapes into the domestic water line. The internal braze may be perforated; in this case the heat exchanger is not repaired but replaced.
• The water is hot when the tap is slightly open but lukewarm when fully open. This means the number of remaining clean channels has decreased.

In hard water areas, limescale is the most common cause. Cleaning with a descaler can be a solution for a while, but if the channels between the plates have narrowed, the permanent solution is replacement.

🪤 Replace the gaskets at the same time. When the heat exchanger is removed and refitted, the old o-rings do not seat properly and leak. On the Beretta side, the gasket code is R10025067.

Technical Specifications