If the white wire is not used, the 28mm zone valve is wired in the same way as the 5-wire 22mm zone valve, and operates in the same way. It is now relatively unusual for the white wire (6 th wire) of a Honeywell 2-port zone valve to be used. Push it towards the MAN OPEN end of the slot and lift while releasing it, so it settles into the hook at the top of the slot. In the past, Honeywell told us that the motors made for them produced a higher level or torque than the standard SYNCHRON motor.

The rotating shoe valve such as danfos have pop-riveted orange wired motors that are suseptable to resistance of movement in the water section caused by magnatite locating between the rotating shoe and the valve body. The most common by far are the 22mm 3-port, 5-wire, mid-position valve and the 22mm 2-port, 5-wire, zone valve.We also think that all the removable powerheads carried the “pip” (or raised bump) on the top of the powerhead metal case, but we are not certain of this.

Inside a Honeywell V4073A 3-port motorised valve showing the rubber ball which closes one or other port, never both. You set the valve into the manually open position by turning the power off, then pushing the lever towards the Man Open end of the slot. Note that the grey and orange wires are used differently from the grey and orange wires of the 2-port valve! I am happy with that because snow is forecast this weekend but I just want to know if this fee is considered OK as I may need to use them again. If it’s the other way round, and the 2-port valve controlling the hot water circuit is failing, it may be less obvious.Otherwise, if several zone valves were used without auxiliary circuits, and all were connected to the same pump so that the Live wire that opened each valve also fed the pump Live, there would be problems. They don’t usually come right out of the steel plate but are retained by it as the powerhead is lifted away from the valve body. The powerhead contains the motor, which is used to drive the valve open, and an auxiliary switch or end switch.