Rotary Thermosta

Thermostat regulating the outlet water temperature, fitted in the unit's electrical box. Operated via an external knob.

Application

The thermostat controls the burner's operation based on a signal from the water temperature sensor fitted at the outlet of the heating coil. Once the set temperature is reached, the thermostat switches the burner off, and switches it back on when the temperature drops, maintaining a constant outlet water temperature.

Symptoms – when to replace

• Water temperature doesn't match the knob setting, despite a sound burner and sound temperature sensor.
• The burner doesn't switch off after reaching the set temperature, leading to overheated water.
• The burner doesn't start at all despite the temperature being set above the minimum (usually 40°C).
• Unstable, fluctuating water temperature during operation, despite a constant thermostat setting.

How to choose the right part

Selection is based on reference number 44167 – it's definitely worth comparing it with the marking on the removed thermostat before ordering, since the technical documentation for related models sometimes shows a different number (44.951) for an analogous component.

When replacing the thermostat, also check the condition of the water temperature sensor (fitted at the coil outlet) and the knob (Drehgriff Thermostat, 44.153) – no response to adjustment can stem from any of these components.