The EGWW sensor is obsolete and needs to be replaced.
EGWW 120 Cu 5122720000
EGWW 120 St 5122720010
Obsolete sensor needs to be replaced.
There is no direct replacement, as the old EGWW had 2 sensor elements and was designed to be used with controllers like TA 219WB (Data sheet here). Also, the EGWW was designed to be mounted directly into the pipe work using a well, and not using a pocket as with the STP100.
If only one sensor element is required by the application, the STP100 series sensor is recommended. However, please note that the EGWW well was 120mm or 220mm (see data sheet here), while the STP100 sensor probe and pockets are available in 50, 100, 150, 200, 250, 300 and 400 mm lengths. For more information and details on the STP100 and its different configurations, please see data sheet here.
If the 2 sensor configuration is required, you will have to install 2 parallel sensors.