A hoseless sensor system for a refrigerant unit includes a plurality of hoseless sensors for sensing system parameters of the refrigerant unit, and a portable electronic device configured to receive the system parameters from the hoseless sensors and to calculate system conditions for the refrigerant based on the system parameters. The plurality of hoseless sensors includes a hoseless first pressure sensor and a hoseless second pressure sensor, and a hoseless first temperature sensor and a hoseless second temperature sensor. The temperature sensors are temperature sensor clamps. Each temperature sensor clamp includes a clamping portion configured to clamp on a tube of the refrigerant unit, the clamping portion including a sensor element to measure temperature about the tube. The clamping portion further includes a plurality of clamping teeth, and adjacent clamping teeth interlock in an overlapping configuration when the clamp closes inward beyond a threshold point.