Pressure Controller - S/D Series

The S/D series is the heavier pressure controller for plant where the KP range is not robust enough, or where the switching point has to be set and locked. The bodies are larger, the bellows are rated higher, and the models are split into low pressure (S102X to S110X) and high pressure (S120X and S130X) versions.

Low pressure models run from -0.02 to 1 MPa with differentials from 0.025 to 0.3 MPa, and the high pressure models from 0.5 to 2 MPa or 0.5 to 3 MPa with differentials up to 1 MPa. Factory settings are published per model, so a replacement can be ordered already set to the original duty - useful where the equipment is in a remote location and a technician will not be revisiting.

Maximum bellows pressure is 1.65 MPa on the low pressure and S110X models, and 4 MPa on the high pressure models, which gives a generous safety margin over the working range. The connection is 1/4 inch NPT, 1/4 inch G, or a capillary, and the allowable fluid temperature is -45 C to +120 C - wider than the KP range, so the same controller suits freezer plant and hot gas lines.

Two features are worth knowing. The micro-switch is a renovated structure with a defined snap action, which matters on plant where the switch operates frequently. And the controller has a manual test function, so the cut-out can be proved during a service visit without valving off the system - on a pump-down circuit that is the difference between testing the safety device and assuming it works.

Mount with the diaphragm vertical where possible, and protect the capillary from vibration.