Heatmiser UH4 - 4 Zone 230v Wiring Centre Item Description: Heatmiser UH4 The Heatmiser UH4 can be used in conjunction with our mains thermostats. The UH4 is also ideally suited for underfloor heating. When used for under-floor heating an option is available to use zone 4 for conventional radiator control. Item Specifications: ---The UH4 provides central switching of up to 4 zone actuators ---Output for a hot water cylinder and the system boiler and pump. ---UH4 Dimensions 384x148x60mm.