Baxi Valve Actuator 3 Port HSA3

The Baxi HSA3 is a three-port valve actuator, supplied as the actuator head only. It is the motorised section of a mid-position three-port valve, mounted on top of the brass valve body. When the programmer or room thermostat calls for heat or hot water, the actuator motor drives the valve spindle to direct flow between the heating circuit, the hot water cylinder and the return.

Because only the head is supplied, the existing valve body, pipework and wiring centre connections are retained.

• The valve head stays in one position and does not move when heating or hot water is called for
• The motor runs continuously or buzzes without driving the spindle
• Heating comes on when only hot water is selected, or hot water runs cold when the cylinder is calling
• The actuator body is warm, discoloured or shows signs of a burnt-out motor
• Radiators stay cold while the cylinder heats, or the reverse, with no change at the valve

• Check the part number on the existing actuator head against HSA3 before ordering
• Confirm the valve body it mounts to is a three-port mid-position type and that the head fixing matches
• Isolate the electrical supply to the heating system before removing or refitting the actuator
• Note the wiring connections and valve position before dismantling, as the head must be refitted in the correct orientation