Vaillant ecoTEC Exclusive 832 838 ecoTEC Plus VUI 937 Boiler Flow Sensor 178988

Product Overview

The Vaillant Boiler Flow Sensor (Part Number: 178988) is a water flow detection component designed for selected Vaillant heating systems.

Part number 178988 is identified in Vaillant's technical documentation as a Flow Sensor (Black), forming part of the boiler's domestic hot water hydraulic control arrangement.

The flow sensor detects water flow within the system, providing information used by the boiler's electronic controls to respond to domestic hot water demand.

Correct flow detection is important for reliable hot water operation and appropriate boiler response when a hot water outlet is opened.

ℹ️ Product Condition Options:

This part may be available in New or Refurbished condition. Please select your desired option from the dropdown menu above. Refurbished components should be professionally inspected and tested to confirm correct operation before installation.

Technical Insight & Common Failure Symptoms

The flow sensor forms part of the boiler's domestic hot water control system. It detects water movement and provides a signal to the appliance's electronic control system when domestic hot water is required.

A fault affecting the sensor, its electrical connections or the associated water flow arrangement may interfere with the boiler's ability to recognise hot water demand.

Possible symptoms that may indicate a flow sensor or associated component problem include:

• Boiler failing to respond when a hot water tap is opened.

• Domestic hot water failing to heat correctly.

• Intermittent hot water operation.

• Boiler failing to recognise domestic hot water demand.

• Irregular response to changes in water flow.

• Electrical connection or flow detection-related faults.

• Visible damage or leakage around the sensor connections.

These symptoms do not necessarily confirm a faulty flow sensor, as similar problems may result from water flow restrictions, wiring, electrical controls or other hydraulic components. Correct professional diagnosis should be carried out before replacement.

Compatibility

This part (MPN: 178988) is associated with selected Vaillant ecoTEC Exclusive and ecoTEC Plus boiler systems.

Please verify the exact boiler model, serial number, part number, sensor configuration and hydraulic connections against the manufacturer's technical documentation before ordering to ensure correct fitment.

Safety Advice

Boiler flow sensors and associated electrical and hydraulic components should only be inspected, removed or installed by a suitably qualified and competent heating engineer.

Always isolate the appliance's electrical supply and relevant water supplies before carrying out any work. Allow the system to cool and safely release residual pressure before removing the sensor. Follow the manufacturer's servicing instructions and complete all required electrical, leakage and operational safety checks before returning the boiler to service.