Filling, Venting, Draining
Data Center
Filling, venting and draining are the three operations that bring a water-glycol loop into service, keep it there and empty it again for maintenance. Trapped air reduces heat transfer at the cold plate, causes flow noise and lets circulation pumps run dry, while residual coolant in the return line prevents a clean component swap in a live rack. This branch groups 86 items for those tasks: brass drain and vent valves, water drain valves with sealing ring, polypropylene drain cocks and plastic filler plugs with air filter and dipstick.
Selection follows the mounting position and the material. Vents belong at the highest point of the loop, drain cocks at the lowest, and filler fittings sit on the tank lid, where the air filter equalises pressure as the fluid level drops. In the water-glycol loop of an IT cooling system, stainless steel and the plastics PP, PE, PVDF, POM, PTFE and PVC are usable without restriction. Brass, gunmetal and bronze stay limited to single-alloy installations, and galvanised steel and aluminium are ruled out.
Categories
The four groups compared
| Criterion | Automatic and Manual Air Vents | Drain Valves and Drain Cocks | Filling and Make-Up Valves | Filling Stations and Storage Tanks |
|---|---|---|---|---|
| Function in the loop | release trapped air | empty the loop, drain condensate | fill the loop and replace losses | hold reserve fluid, automate filling |
| Mounting position | highest point | lowest point | tank lid or make-up point | beside the loop |
| Ports | G 1/8 to G 1/2, R 1/8 and R 1/4 | G 3/4" plus canister threads DIN 45, 51 and 61 | G 3/8 to G 1", M 16x1.5 to M 22x1.5 | not yet defined |
| Materials | brass, partly chrome plated | brass and polypropylene | plastic | not yet defined |
| Items | 22 | 8 | 56 | 0, range under development |
Materials in the water-glycol loop
| Material | Suitability | Note |
|---|---|---|
| Stainless steel, PVDF, PP, PE, PTFE, POM, PVC | unrestricted | default choice for newly planned IT cooling loops |
| Brass, gunmetal, bronze, copper | only in single-alloy installations | no mixed metals in the same loop |
| Galvanised steel, aluminium | do not use | corrosion and galvanic action in a mixed loop |
- Commissioning a new direct liquid cooling loop: filling through the filler plug, venting at the manifold until the flow is free of bubbles
- Topping up at the expansion tank after maintenance or evaporation losses
- Draining a rack branch before replacing a cold plate, hose or pump
- Removing condensate and residual water from low-lying pipe sections
- Decanting water-glycol mixture from plastic canisters with DIN 45, 51 or 61 threads
- Flushing and refilling the loop when the inhibitor package is changed
