Learn how to install a ball valve with drain through simple steps, safety checks and expert tips
Ball valves with integrated drains are designed to simplify maintenance, system shutdown, and fluid evacuation in industrial and civil piping networks. This configuration, which typically features a side drain outlet, allows users to discharge residual fluids from the system without having to disassemble pipes. Installing a ball valve with a drain not only improves system reliability and safety, but also reduces downtime during maintenance and seasonal shutdowns.
System preparation before installing a ball valve with drain
Before proceeding to install a ball valve with drain, it's crucial to ensure that the system and installation environment are properly prepared to guarantee safety, functionality, and long-term sealing performance:
- System depressurisation: if you’re installing a valve in an existing pipeline, make sure the pipeline is not under pressure and that all fluids are drained before disassembly.
- Compatibility check: verify that the valve configuration, its materials (body, seals, ball) and pressure / temperature ratings are compatible with the media. There must be enough space for the handle to operate the valve.
- Correct orientation: identify the flow direction – if applicable – and ensure the drain port is accessible after installation.
- Thread or flange matching: confirm that the valve end connections match the piping specification (BSP, NPT, ISO 228 or ISO 5211 flanged if actuator-ready).
How to install a ball valve with drain
To ensure a reliable and leak-free setup, follow these step-by-step instructions to correctly install a ball valve with side drain:
- Apply thread sealant or PTFE tape: wrap the male threads in the direction of tightening. Do not over-apply to avoid stressing materials.
- Align the valve body: ensure that the valve is in closed position before mounting. Position the drain port facing downward or sideward, depending on ease of access to the drain port and application requirements.
- Tighten the connections: hand-tighten the valve to the pipeline, then use an appropriate wrench applied to the hex where pipe is being installed, to secure tightness. Avoid over-tightening, which may damage the valve body or its threads.
- Check drain port closure: the side drain should be closed using the supplied plug or connected to a suitable drain line. RuB S.81 come with a brass drain plug as standard.
- Pressure test: gradually pressurise the system and check for leaks at the main connections and drain port.
NB: each box of RuB valves includes Installation Maintenance and Operating instructions.
Spotlight on the RuB S.81 drain ball valve
One notable example is the RuB S.81, a two-piece full bore ball valve with an integrated side drain port, designed to enable easy emptying of media downstream of valve when the valve is closed. This function is particularly useful to prevent freezing, contamination, or pressure build-up in fluid systems, and to effectively drain excess fluid during maintenance or shutdown. Engineered for safe and efficient installation, the S.81 features a full port design that reduces turbulence and pressure drop, as well as threaded connections for straightforward integration. Its blowout-proof stem enhances operational safety. The valve is available in sizes ranging from 1/2” to 2”, making it suitable for a wide variety of civil and industrial applications, including irrigation systems, water distribution lines, heating circuits, seasonal installations, process lines that require purging or cleaning, and compressed air systems with condensate evacuation.
NB: the valve shell itself does not withstand freezing.
Final steps to install ball valve with drain and ensure long-term performance
To complete the installation correctly and ensure long-term system reliability, it is essential to follow the manufacturer's recommendations, such as those detailed in the Bonomi Industries Installation Maintenance and Operating instructions enclosed in each box of valves. This includes using quality sealing materials, applying correct tightening torque to prevent mechanical stress, and ensuring that the drain port remains accessible for maintenance and operation.
For further technical guidance, including dimensional data and actuator compatibility, Bonomi Industries’ engineering team is available to support your project.
Need help choosing the right drain valve for your application? Contact our team for tailored support or consult the full specifications of the RuB S.81 series to ensure optimal integration into your system.