Drain Valves and Drain Cocks
Filling, Venting, Draining
Drain valves and drain cocks sit at the lowest point of a loop and release its contents in a controlled way before cold plates, hoses or pumps are replaced. The category holds eight items: EWV brass water drain valves with sealing ring in G 1/2" and M 22x1.5, polypropylene drain cocks in G 3/4" rated PN 0 to 2 bar and PN 0 to 4 bar, drain cocks for plastic canisters to DIN 45, DIN 51 and DIN 61, and one fully automatic drain valve with a G 1/8 female to M14x1 adapter.
Two figures govern the choice: the thread at the drain point and the permissible pressure. The polypropylene versions are rated for low pressure and belong on tanks and collecting trays, not in a supply line under working pressure. Plastic keeps copper alloys out of the wetted path and is unproblematic in a water-glycol loop, whereas the brass versions require a single-alloy installation. The canister cocks with 4, 5 and 6 mm thread pitch are used for decanting from containers.
Drain points and matching fitting
| Criterion | EWV water drain valve | Plastic drain cock | Canister drain cock | Fully automatic drain valve |
|---|---|---|---|---|
| Connection | G 1/2", M 22x1.5 | G 3/4" | DIN 45, 51 and 61 | G 1/8 female to M14x1 adapter |
| Material | brass with sealing ring | polypropylene | plastic | not specified |
| Pressure rating | not specified | PN 0 to 2 bar, PN 0 to 4 bar | unpressurised | not specified |
| Actuation | manual | manual | manual | self acting |
| Mounting position | lowest point of the loop | tank and collecting tray | container | collection point |
- Draining a rack branch before a cold plate, hose or pump is replaced
- Removing residual water from low-lying pipe sections after a pressure test
- Emptying the expansion tank before an extended shutdown
- Decanting water-glycol mixture from plastic canisters with DIN 45, 51 or 61 threads
- Taking samples to check glycol content and conductivity
- Draining condensate from collecting trays beneath the coolant distribution
