How to enable the two NRP units to function as Master and Slave

You need to connect the two unit controllers (PCO3) in Plan network so it is necessary to connect the two Pco3- terminals J11

Then there is also the microPC cards and on B3 (MASTER) plant common leaving water temperature, connect the common temperature probe (NTC10 kohm) and enable it on parameter H24 B3=Y.

SETTINGS ON MASTER unit (example of version 4 pipes like NRP0750E4….)

on menu PLANT CONFIGURATION the parameter H42 you select the MASTER or SLAVE configuration.

On parameter H45 you select the STEP parameter (how to control the two units). For istance setting step=1 the two machines are in parallel but selecting 100% for instance they are in cascade. On parameter H48 you can select (in case the water pumps are on board) when to stop the SLAVE water pumps (no request pumps off)

The B4 on last NRPs where there are two exchangers on recovery side, one per circuit, is already installed but must be remoted on common heating leaving water pipe.

When there is the 2 pipes type NRP0750E2….

You have this setting on parameter Q3 (setting temperature control on buffer tank, placing the B5 there and enabling B5 on parameter H24) plus the parameter Q21 where you fix the setpoint on unit outlet side (B4)