A hydronic system (1) includes a side (3) with a first port (21) connected with a source element output (23), a second port (27) connected with a source element input (29), and a controllable primary side flow actuator (9) for providing a primary side flow (q1). Another side (5) has a third port (31) connected with a load element input (33), a fourth port (35) connected with a load element output (37), and a controllable secondary side flow actuator (13) providing a secondary side flow (q2). A transfer element (17) is connected with the first port, the second port, the third port and the fourth port. A flow control module (39) adapts a transfer element thermal power transfer by controlling the primary side flow actuator and/or the secondary side flow actuator by minimizing a signed deviation value (ΔΔv) that is correlated with the transfer element thermal power transfer.