Hvac 8 zones of controll

[reaper7]

Hi I wish to Implement 8 zones of heating controll into my system.
What is the best way to do this as the largest controller I've seen is 6 zones.
Can you use two of these with rs-232 to controll each zone (Driving an Actuator on each zone for on/off switching of underfloor heat loops). :confused:

[znelbok]

Where are you - if you are Downunder you can try AdvantageAir, they can do up to 32 zones.

Mick