To add this control mode the sensor kit will be a Grundfos RPI 16.0 232 psi, P/N 98477668 (1/4″NPT) or P/N 98477669 (1/2″NPT) with the specifications below:
For constant temperature, wire to the analog input, ground, and +24V terminal. Then go into the settings for that analog input and choose Function: Feedback sensor, Measured: Liquid temp., 0-10V, Fahrenheit, Min: 14, Max: 248. Then change the control mode to constant temperature and choose your setpoint.
For constant differential temperature you will need two of the same sensor, wire them the same way mentioned above, but one for analog input 1 and the other for analog input 2. Make sure to use separate +24V terminals. When you go into the settings they will be identical to the settings mentioned about except “Measured” needs to be “Temperature 1” and the other “Temperature 2”. Once those are set change your control mode to differential temperature and choose your setpoint.
Depending on the application, when using constant differential temperature you may want the pump to speed up or slow down when the actual temperature differential is below the setpoint. If you want the pump to speed up in this case, there is no need to change any other settings. If you want the pump to slow down, we will need to change the Kp value to a negative number.
For additional support, contact a Grundfos Applications Engineer at 1-844-994-2850.