A new 2 port valve, fitted on the copper pipework next to a hot water cylinder.
The first photograph is the valve in place beside the white cylinder, its grey head above a copper pipe joined to a copper tee, with the cylinder thermostat on the left and a wiring box on the right.
Two ports, one motor
A 2 port valve has two ports, one in and one out, and a small motor in the head that opens and shuts it. It sits on a pipe of heated water and does nothing on its own. When the controls call for heat, the motor drives the valve open and the water goes through. When the call stops, the valve shuts again and the water stops there. The other half of its job is telling the boiler. The head is wired back into the heating controls, and through that wiring the boiler is told there is a call for heat, so it only runs when something is asking for it. That is why a motorised zone valve, to give it its longer name, is part plumbing and part electrics. The body is fitted into the copper pipe, the head is wired into the controls, and both halves have to be right before the valve does its job.
The wiring centre
The second photograph is an open cream box on the cylinder, its terminal strips holding brown, blue, green-and-yellow, grey and red wires, with a white cable running down into it.
That box is the wiring centre, where the heating controls are joined together. The new valve is wired into it.
Signs of trouble
A 2 port valve not working usually shows up as heating or hot water that will not come on.
A valve stuck closed keeps the heated water out of its pipe whatever the controls ask for. One stuck open lets it through when it should not. The signs are the heating working without the hot water, or the other way round, or one staying on when it should be off.
This job was a new 2 port valve, fitted and wired in.
Same firm
Our electrical page says it is the same firm as the plumbing, and a 2 port valve needs both: copper on one side, wiring on the other.
A room thermostat is one of the controls calling for heat, as in the wireless room thermostat installation we wrote up, and the immersion heater element post is another job on a cylinder.
Ring 07546 185778 and tell us what the heating and hot water are doing, with a photograph of the valve if you can.
