Yes, to replace the old thermostat, the Sensor PRO (code 215002/215002 BLK) with the Gateway (code 215100/215100 BLK) or the Gateway PRO (code 215015/215015 BLK) can be used without installing the controls on the radiator. Naturally, without Comfort Controls, you will not have the benefits of modulating regulation, which would ensure greater efficiency and, as a result, greater energy savings.