Not exactly. The old style vented check that had the pilot port in the end of the hex body, and vented out port 3, had what we call a proportional pressure reducing feature. The poppet stem was exposed to the vented area and the stem area was about ¼ of the area of the poppet seat. The result was that you could only develop 75% of the pressure at the actuator. If system pressure was 3000 psi (210 bar), the highest pressure at the actuator was about 2250 psi (155 bar). The part numbers for the old style valves are

CKCE CKEE CKGE CKIE CKCF CKEF CKGF CKIF CKCG CKEG CKGG CKIG CKCH CKEH CKGH CKIH

In our 1992 catalog we introduced a new design of vented pilot-to-open check valves, eliminating the proportional pressure reducing feature to allow full system pressure at the actuator. The pilot is now at port 3. This allows the vented counterbalances and the vented checks to share the same manifolds. The new design incorporates more spring force to lessen the chance of false piloting (see the FAQ on where to vent). The new design allows us to offer valves that are vented out of a port in the hex body.

We do have new design valves that replace the old style (pilot in 3 and vent out the hex body). These should be used with caution. If you are replacing the old style that had the pressure reducing feature you will realize a 33% increase in actuator force. The part numbers for these are CKCI, CKEI, CKGI, and CKII.

The venting of the new design is not entirely pure. There is an area exposed to the vent area that opposes the poppet spring. Piloting a valve open is a very remote possibility but 450 psi (30 bar) in the vent area could hold the poppet open.