Tekmar tN2 Zone Exp. Module-4 zones, cooling&fan. tekmarNet??2 Zone Expansion Module 324 is designed to provide expansion for a zoning solution used in heating systems. It can be used in applications ranging from baseboard zones, to remote manifolds for radiant heating. This product expands number of zones in a heating system by up to 4 zone valves or zone pumps. It is capable of providing power for up to 4 tekmarNet??2 rmostats and energizing ir respective 24 V (ac) or 115 V (ac) zones, as well as providing a powered Zone Group Pump (powered end switch) contact to enable an external device such as a manifold pump.