By STILONN Valves & Controls Pvt. Ltd. | Reading time: 7 minutes
AI servers have changed the arithmetic of data center cooling. A single rack now draws more power than an entire row did a few years ago, and air alone cannot carry that heat away. Liquid has taken over: coolant is piped directly to cold plates on the chips, and a network of stainless steel piping, manifolds and valves moves it there and back, every second of every day.
In that network, valves are small items on the bill of materials and large items on the risk register. A valve that leaks, sheds particles or fails to isolate can take a row of GPU servers offline. This article explains where valves sit in a liquid-cooled data hall, what makes the duty different from ordinary chilled-water work, and what to ask of a valve supplier.
Where the valves sit
A direct-to-chip system has two liquid circuits. The facility water system carries heat out of the building. The Secondary Fluid Network (SFN), also called the technology cooling system, is the clean closed loop between the Coolant Distribution Unit (CDU) and the racks. The two meet only at the heat exchanger inside the CDU.
The SFN is where valve count climbs quickly. Supply and return headers run above or below the racks, each rack takes a pair of drops, and every drop needs its own isolation so one rack can be serviced without disturbing its neighbours. Add balancing on branches, strainers and filtration at the CDU, non-return valves at the pumps and vents at the high points, and a single data hall can carry thousands of valves.
Why SFN duty is not ordinary HVAC duty
- The coolant passages are tiny. Cold plate micro-channels are easily blocked. Machining residue, weld scale or seat debris from a valve travels straight to the chip. Cleanliness of every wetted part is a functional requirement, not a finishing detail.
- Leaks are not tolerated. Coolant runs directly above or beside IT equipment worth many times the cooling plant itself. Seat and stem sealing must stay tight over years of continuous service.
- The fluid chemistry is controlled. Most loops run treated water or a propylene glycol mix with inhibitors. Body material and elastomers must be compatible with it and must not leach into it, which is why stainless steel has become the standard choice for SFN components.
- There is no convenient shutdown. The loop runs 24×7. Valves must allow rack-level maintenance while the rest of the hall stays live, and they must operate reliably after sitting in one position for months.
- Installation speed matters. Projects are built on compressed schedules. End connections that assemble quickly and repeatably, such as grooved ends, reduce site welding and help keep the loop clean.
Valve types and their roles
| Valve | What it does in the loop | Typical location | STILONN range |
|---|---|---|---|
| Ball valve | Positive isolation with a full-bore, low pressure-drop flow path | CDU connections, header ends, every rack drop | SS ball valves, including the LCGD grooved-end series |
| Butterfly valve | Isolation and flow control on larger line sizes in a compact body | Main supply and return headers, CDU skids | SS butterfly valves, manual or actuated |
| Balancing valve | Sets and holds the design flow for each branch | Row manifolds and branch lines | Balancing valves |
| Strainer | Catches particles before they reach cold plates and quick couplings | CDU inlet, filter skids, branch inlets | Strainers |
| Non-return valve (NRV) | Stops reverse flow and protects pumps | Pump discharge, redundant loops | NRVs |
| Air vent valve | Releases trapped air that causes noise, flow loss and hot spots | High points of headers and manifolds | Air vent valves |
What to specify
- Material: stainless steel wetted parts. STILONN supplies SFN valves in SS304L, the grade widely used for SFN piping, so valve and pipe match.
- Seals: seat and seal materials confirmed against the actual coolant and its inhibitor package.
- Cleanliness: valves cleaned, assembled and packed in a controlled environment, with ends capped until installation.
- End connections: grooved, flanged or tri-clamp to suit the piping design and the installer’s method.
- Testing and records: pressure and seat leak testing before dispatch, with material traceability and test certificates in the handover pack.
- Support: a manufacturer who can attend site during installation and commissioning, not only deliver boxes.
How STILONN approaches SFN valves
STILONN has manufactured stainless steel valves since 2008, starting with hygienic and sanitary valves for pharmaceutical, food, dairy and biotech plants. Those industries demand the same things an SFN loop does: clean internal surfaces, compatible seals and dependable shut-off. That experience is the base on which STILONN became India’s first manufacturer of SFN valves for data center liquid cooling.
Purpose-built range
Ball valves, butterfly valves, balancing valves, strainers, NRVs and air vent valves in SS304L, along with gaskets for liquid and hybrid cooling. The LCGD series of grooved-end ball valves is designed for fast, weld-free installation on grooved SFN piping.
Clean assembly
Hygienic and liquid cooling valves are assembled in STILONN’s ISO Class 8 clean assembly area, so cleanliness is built in at the factory rather than left to site flushing.
Made in India, backed by a group
Manufacturing is based in Navi Mumbai and Chiplun, Maharashtra. STILONN is an Aeroflex Group company; together with Aeroflex Industries and HYD-AIR Engineering, the group covers valves, piping, manifolds and related liquid cooling infrastructure, and welcomes customer factory visits.
Service on call
For data center projects in Navi Mumbai and within 50 km, STILONN runs a 24×7 service and site support team for valve installation, troubleshooting, SFN technical queries, commissioning and emergency calls.
A short checklist before you order
- Is every wetted part stainless steel and compatible with your coolant?
- Where and how is the valve cleaned, assembled and packed?
- Do the end connections match your piping system?
- What test and traceability documents come with each valve?
- Can the manufacturer support installation and commissioning at site?
Talk to STILONN
Planning a liquid-cooled data hall, a CDU skid or an SFN piping package? Share your valve schedule or P&ID and our team will respond with selection support and a quotation.
Email: info@stilonn.com | Service line / WhatsApp: 8655795716 | www.stilonnvalves.com
