A heat exchanger includes a sensor grid with sensor leads extending through tube restraints for heat exchange tubes in the heat exchanger. The tube restraint includes a body having a plurality of tube openings defined therein with each tube opening receiving one heat exchange tube of the set of heat exchange tubes therethrough. The body also includes a sensor lead opening defined therein to receive a sensor lead therethrough. Each tube opening has a larger dimension than the sensor lead opening. The sensor grid is installed during manufacture rather than in the field, allowing the sensor grid to be on outermost and inner sets of heat exchange tubes in the heat exchanger.