Walk into almost any new high-density compute facility today and you'll find the same story playing out. Racks that used to pull 10 or 15 kilowatts are now pulling 60, 80, even 120 kilowatts, thanks to the GPUs and CPUs powering AI training and inference workloads. Air cooling simply can't keep up with that kind of thermal density anymore. So the industry has shifted, almost universally, to direct-to-chip liquid cooling — cold plates mounted right on the silicon, with coolant carrying heat away far more efficiently than air ever could.
It's a great solution. But it introduces a problem that a lot of facility teams don't think about until it's already costing them: air.
Why a Little Air Causes a Lot of Trouble
Liquid cooling systems are only as good as their contact with the heat source. Any pocket of air that gets trapped at a cold plate, manifold, or high point in the piping acts as an insulator right where you need heat transfer to be at its best. Even a small air gap on a cold plate can create a localized hot spot, which is exactly the failure mode these systems were designed to prevent.
It doesn't stop there. Trapped air collecting in a pump housing leads to cavitation — that's the noisy, damaging condition where air pockets collapse violently against impeller surfaces, chewing away at metal over time and shortening pump life. Air also carries dissolved oxygen, and oxygen in a closed loop means corrosion, which means scale and debris that can clog small-diameter cold plate channels. And because these loops are pressurized and dynamic, air that seems harmless on day one tends to migrate, settling at high points and manifold tops where it interferes with flow sensors and balancing valves.
Here's the part that catches people off guard: you don't have to do anything wrong for air to show up. It enters during initial fill and commissioning almost no matter how careful the install crew is. It comes in with makeup fluid. It comes out of solution as the coolant warms up, since warmer liquid simply can't hold as much dissolved gas as cold liquid. Every time a quick-disconnect fitting gets used during maintenance, there's another opportunity for a little air to sneak in. In other words, trapped air isn't a one-time commissioning issue — it's an ongoing condition that liquid cooling systems have to manage for as long as they're running.
Why You Can't Just Vent It Manually
The old-school answer was a technician with a wrench, manually cracking a valve at each high point to bleed air, then closing it back up. That might work for a single chiller loop you can take offline once a quarter. It does not work for a data hall full of CDUs and manifolds running 24/7 under live compute load. You can't schedule downtime every time a few cubic centimeters of air accumulate somewhere in the loop, and by the time a problem is visible on a monitoring dashboard — a temperature spike, a flow alarm, a noisy pump — the air has probably already done some damage.
What these systems need is something that handles venting on its own, continuously, without anyone having to notice the problem first.
How Armstrong's Automatic Air Vents Solve It
This is exactly the role Armstrong's stainless steel automatic air vents are built for. The design is refreshingly simple and mechanically reliable: a free-floating, guided lever mechanism sits inside an all-welded stainless steel body. As liquid fills the vent, the float rises and the vent stays sealed. As air or other gas accumulates and the liquid level inside the vent drops, the float falls and opens the vent, releasing the trapped gas. Once the gas is gone and liquid returns, the float rises again and the vent closes — positively and leak-tight, with no manual intervention, no electricity, and no controls programming required.
Because the body and cap are welded into a single sealed unit rather than gasketed together, there's no joint to fail and no seal to maintain over years of continuous service. These vents are rated for serious operating pressure — many models handle several hundred psig — which makes them well suited to the pressurized, high-flow conditions found in CDU loops and rack manifolds, not just low-pressure hydronic systems.
Installed at the high points of the loop — at CDU outlets, manifold tops, and anywhere else air is likely to collect — these vents do their job continuously and automatically, keeping the system fully primed without taking anything offline. That keeps cold plates in full contact with coolant, keeps pumps running quietly and free of cavitation damage, and keeps the whole liquid cooling system operating at the efficiency and reliability that high-density compute demands. For data center operators chasing lower PUE and higher uptime, that's not a small thing. It's the difference between a cooling system that quietly does its job and one that generates support tickets.
Where to Get the Right Guidance
Specifying and placing air vents correctly across a CDU loop or rack manifold isn't something you want to guess at, and that's where having a knowledgeable partner matters. Energy West Controls, headquartered in Salt Lake City, Utah, has represented Armstrong International's steam, condensate, hot water, and fluid control products across the Rocky Mountain region for more than four decades. Their team of factory-trained sales and applications engineers works directly with facility engineers and contractors to size equipment correctly, identify the right vent models and placement for a given loop design, and support projects from initial design through commissioning and beyond.
If you're designing, retrofitting, or troubleshooting a direct-to-chip liquid cooling system and want to make sure trapped air isn't quietly working against you, Energy West Controls is a solid first call. Reach their Salt Lake City headquarters at 801-262-4477 or through energy-west.com, where their engineers can walk through your system specifics and recommend the right Armstrong air vent solution for your facility.