Kingston 620-3 Pneumatic Automatic Tank Drain Valve, 3/8 in NPT Inlet, Brass

The Kingston 620-3 is a pneumatically operated automatic drain valve for air compressor receivers. It runs on the compressor's own air with no electrical supply, no timer and nothing to program, so the tank gets drained whether or not anyone remembers to do it.

Condensate left in a receiver does real damage: it corrodes the shell from the inside, carries water downstream into tools and finishes, and shortens the life of the vessel. A manual drain only solves that while somebody is still bothering to open it.

Specification

• Part number: S1071, Kingston 620-3
• Inlet: 3/8 in NPT female
• Outlet: 1/4 in NPT female
• Body: brass
• Maximum pressure: 400 PSI
• Temperature range: -40 to 225 F
• Operation: pneumatic, no electrical supply required

Where it suits

Shop and industrial reciprocating compressors, and any installation where running power out to a drain point is awkward. The 400 PSI rating gives it a lot of headroom over normal shop pressures, and the brass body holds up better than plated steel in constant contact with condensate.

For a zero air loss drain on a larger or continuously loaded system, look at the Drain-All pneumatic drains. For a timed electric drain we stock those from 1/4 in through 1 in.

Fitting it

Blow the tank down to zero and confirm it on the gauge before you open the drain port. Fit the drain at the lowest point of the receiver; plumbed any higher it leaves a permanent pool of water underneath it. Pipe the discharge to a place you are happy for oily water to go, keep that line short and no smaller than the outlet, and avoid running it uphill.

Use pipe thread sealant rather than tape. Tape shreds and ends up on the seat, and a drain valve held open by debris bleeds the tank continuously.

Related parts

We also stock the Conrader WV-1 pneumatic automatic drain, Drain-All zero air loss drains, electronic timed drains, bucket high drop leg drains and pet cock tank drains.

Kingston 620-3 pneumatic automatic tank drain valve with a 3/8 in NPT female inlet and 1/4 in NPT female outlet, brass body, rated to 400 PSI.