Vaillant Sensor 0020059717 Vcw Vuw 20059717 253595

GLOWWORM 0020079644

The Vaillant Water Pressure Sensor (Part No. 0020059717) is a critical electronic component that monitors the static and dynamic water pressure within the boiler's primary heating circuit. It provides real-time data to the PCB, ensuring the boiler only operates when the system is adequately filled. This sensor is the direct replacement for the older part number 253595 and is a staple spare for the VCW and VUW (ecoTEC) ranges.

Key Features and Specifications
Digital Monitoring: Sends a precise voltage signal to the boiler’s "brain" to display the system pressure (in bars) on the digital fascia.

Dry-Mount Design: Features an internal diaphragm that isolates the electronics from the system water, ensuring long-term reliability.

Low-Water Protection: Serves as a primary safety device; if pressure drops below a safe threshold (typically 0.6 bar), the sensor triggers an F.22 lockout to prevent the heat exchanger from dry-firing.

Genuine Vaillant Part: Manufactured to strict OEM standards to ensure the signal calibration matches the requirements of the Vaillant PCB.

Direct Supersession: Fully replaces the discontinued 253595 part number.

Boiler Compatibility
This sensor is widely used across the entire first and second-generation ecoTEC ranges. Compatible models include:

ecoTEC Plus (VC/VCW): 612, 615, 618, 624, 630, 637, 824, 831, 837, 937.

ecoTEC Pro (VUW): 24, 28, 30.

ecoTEC Exclusive: 832, 838.

Note: It is also found in some Home Glow and VUI storage combi models.

Technical Tip: If your boiler is displaying an F.22 (Low Water Pressure) or F.75 (Failure to detect pressure rise when the pump starts) error code—and you have confirmed the system is actually full of water—this sensor is the most likely component at fault. Over time, the internal sensing port can become blocked with system sludge or magnetite.

Installation and Maintenance
The sensor is typically held in place by a simple metal retaining clip. While it is a relatively straightforward "plug-and-play" part, the boiler's primary circuit must be drained to 0 bar before removal to avoid high-pressure water discharge. It is highly recommended to clean the seating area before installing the new sensor to ensure a watertight seal with the included O-ring.

Essential Companion Products
To ensure your system remains pressurized and protected, the following genuine Vaillant parts are often required:

Direct Product Link: Vaillant Sensor - 0020059717

Safety Relief: Vaillant Pressure Relief Valve (3 Bar) - 178985

System Expansion: Vaillant Expansion Vessel - 181051

Temperature Monitoring: Vaillant NTC Sensor (19-3592)

Specialist Support and Local Collection
Are you struggling with persistent F.75 faults? This can sometimes be related to the pump rather than the sensor. Our trade counter team can help you diagnose the issue and ensure you get the right part the first time.

Visit our trade counter and Bathroom Showroom at 61 Fullers Road, E18 2QB for expert technical advice and quick access to the full Vaillant spare parts range.