As correct operation relies on the valve internals functioning properly, valve failure will result in some non-obvious situations. Heating only does not work Unlke the Y-plan system, operation of hot water and heating are totally separate, and this layout can easily be extended to support additional heating zones simply by adding an extra valve and thermostat for each zone. It can also be adapted for use with underfloor heating. Operation - Hot water Locate any unconnected wire labeled W or W1. If you identified an O, B, or O/B wire connecting to the O/B terminal in the previous step and it has a separate W wire, place it into the W2 terminal. Connect the W wire to the W terminal if you don’t have a wire connected to the O/B terminal. Regardless of other settings, at least one of the outlets is always open, so it is always possible for water to flow through the valve.

so far i have connected everything apart from the cylinder stat, I was going to use the old switchmaster one that was there but this has different wires and i cannot find any info on it to determine which is which so i will buy a new one tomorrow and fit this in the wiring center shortly The only addition to acheive heating only is terminal 1 (HW Off) of the programmer being connected to power. With no power applied, the spring holds the valve in position B, so water only flows to the hot water cylinder. Power on White only On most valves, the actuator head containing the switches and motor can be replaced as a separate unit without draining the system. On some, the internal motor can be replaced, although it is often easier to change the whole head. Once the valve is fully open, a switch inside connects the grey and orange wires together. Since grey is permanently connected to power, the orange wire provides power to terminal 10 in the wiring centre, and from there to the boiler and pump. Operation - Heating

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Identify any wires labeled R, RH, or RC. You typically have one or two of those three. If you have one wire — even if it’s labeled RC — it goes into the R terminal, setting the jumper connecting terminals R and RC in place. Thermostats may have a jumper switch, metal staple, or plug. The jumper may also be a wire connecting the two terminals. If you have two wires, R or RH go into the R terminal and RC into the RC terminal. If you have more than one wire (for example, you have a wire labeled R and another wire labeled Rc), remove any jumpers between the R and Rc terminals or push the switch to open the RC terminal to insert a wire. It can still be fitted today, however is not suitable for systems with more than one heating zone. 3 Port Valve Operation Your new thermostat may not be directly compatible if you see terminals labeled A B C, or 1 2 3, as your system requires a communicating thermostat.

The motor will move the valve to the mid position AB, so both heating and hot water are selected. Internal switches and other components ensure the motor is held at this mid point. Power on White and Grey

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This scheme uses a 3 port mid position valve. In the past this was by far the most common setup, as it only requires one valve. I have managed to install the reciever and get the relay working OK, and when you adjust the temperature the relay opens/closes and you see the wireless display call for heat with the flame symbol. There is no standard for which color wire controls each function. When wiring, each wire should be identified by what terminal(s) it connects to — never by color. If you don’t know to which terminal each wire connects, it may be necessary to go to the HVAC system and look at the designations on the control board. Consult your owners/install guide for wiring examples and systems compatible with your thermostat*.

Note that although the orange valve wire is connected to power, this does nothing, as orange is only connected via an internal switch when the valve is in position A. Operation - Hot water and central heating These systems contain a wireless controller with a wired receiver unit. The receiver unit replaces the existing programmer. The wireless controller contains a room thermostat and is used to control both the heating and hot water, so any existing wired room thermostat must be removed. To protect your equipment, turn off the power at the breaker box or switch that controls your heating and cooling. To confirm your system is off, change the temperature on your existing thermostat, so the system starts heating or cooling. If you don’t hear or feel the system turn on within 5 minutes, the power is off. You can skip this step if you have a digital thermostat with a blank display. The boiler and pump are switched via the valve. Therefore problems with the valve will mean the boiler never switches on, or in some cases will run continuously.The valve has two plumbing connections - in and out. With no power applied, a spring holds the valve closed so no water will flow. This diagram shows the wiring layout using the most typical components. Here, coloured wires indicate the permanent mains supply to the boiler and programmer. The coloured valve wires are also shown. At the moment I have a wired stat (Servowarm) which has a 3 core and earth cable connecting to it from a Honeywell Wiring Centre. Only two of the cores and the earth are being used at both ends. (Yellow, Red and Earth)

Next, let’s talk about the C or common wire. If you have a Trane model thermostat and a wire labeled X or B, refer to your thermostat manual. In some cases, one of those wires is your common. If you have a C wire, place it into the C terminal on your wall plate. C wire adapters are available here. This video covers the wiring and electrical operation of a Y plan system. Wiring diagrams and further information continues below. View on Youtube. System Wiring Power starts at terminal 3 (HW On) in the programmer. This passes via the wiring centre terminal 6 to the cylinder thermostat. If heat is required, power continues to terminal 8 in the wiring centre, and on to the boiler and pump. Here, power is also applied to programmer terminal 4, which connects via wiring centre terminal 4 to the room thermostat. If heat is required, power continues to terminal 5 in the wiring centre, and therefore to the white valve wire. When the valve is powered and reaches the fully open position, the grey and orange wires are connected together. This is normally used to activate the boiler and pump. Overview Video

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This arrangement is common on new installations, as it allows for multiple heating zones with the minimum of additional plumbing and wiring. 2 Port Valve Referring to your photo, remove and label each wire. If a terminal has multiple designations like W and O/B, it will be labeled as W and O/B and not just one or the other.