Sun Hydraulics’ pilot-to-open check cartridges are non-modulating, on-off devices used for holding a load or actuator in position. Sun pilot-to-open check cartridges can be directly integrated into your actuator or applied using manifolds with many mounting options.
- Offer protection against hose breaks
- Positively lock pressurized loads
- Are available in non-vented (3-port) and vented (3- and 4-port) versions
- Are physically interchangeable with counterbalance cartridges (same number of ports, same cavities, same flow path for a given frame size).

Pilot Operated
- Maximum operating pressure = 5000 psi
- Maximum valve leakage = 1 drop/min.
- CKBB, CKBD available only with 30 psi or 75 psi check valve cracking pressures.
- CK*D has sealed pilot for use in circuits where cross port leakage is undesirable.
- CK*B has unsealed pilot to allow air trapped in the pilot line to be purged from the circuit.

Atmospherically Referenced, 3 Port Cavity
- Maximum operating pressure = 5000 psi
- Maximum valve leakage = 1 drop/min.
- Approximately 1 drop of fluid will pass from the pilot area to the vented spring chamber every
- 4000 cycles.

Vented, 4 Port Cavity
- Maximum operating pressure = 5000 psi
- Maximum valve leakage = 1 drop/min.
- Port 4 (vent) should never be blocked as seal weepage will eventually cause valve to malfunction.
- Will accept pressure at port 4 (vent) but cannot exceed 5000 psi.