One Hawk controller and IO34 module replaced four CSC compensators, then changing the valve heads from ARX actuators fitted to MB valves dating back to 1995 with Belimo HT24-SR's made the system much more flexible with points to spare for future expansion.
A remote mounted touchscreen gives full access to individual zone times, temperature settings and new ECO functions for further energy saving.
The boilers still on their original lead/lag thermostat are now demand-based, only operating when there is a call for heat from any of the four compensator zones.