After removing and labeling all wires, unscrew the old thermostat wall plate and mount the new thermostat’s wall 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. 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 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.

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 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. You should typically see an 18-gauge solid core wire. The most common configuration is five wires. However, you could see as few as two and many as ten.first the history: I have a very old system that hasn't been updated for probably 30 years or so. I have swapped out all the old (rusted/leaking/broken beyond recognition) plumbing connections and in doing so also replaced all the components for modern units (apart from the pump which seems ok) I have not moved anything the positions are all as before. We are currently using Royal Mail Parcelforce and DPD as our delivery providers, all small items will be delivered by Royal Mail, these can take up to three working days to reach you. If the valve motor fails, the valve will remain at position B and hot water will never reach the radiators. Radiators and hot water always work together

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 valve has two plumbing connections - in and out. With no power applied, a spring holds the valve closed so no water will flow. 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. 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 three additional coloured valve wires are also shown (white, grey and orange). 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.

I believe it to be a fully pumped S plan system. 2 x 2 port zone valves and a large water fill and small F/E tank in the loft 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. This is simply the above two diagrams combined. Unlike the Y-plan system, operation of heating and hot water is totally separate, they do not interact or require the presence of the other. Possible problems

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. The valve is not powered at all, and the spring holds it in position B, so water from the boiler only flows to the hot water cylinder. 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 Due to several seconds being required for the valve to move from B to A, there is a delay between selecting heating at the programmer and the boiler starting. Possible problemsThis scheme uses separate two-port valves, one for hot water and another for heating. It can be easily extended to include additional heating zones by adding an extra valve and room thermostat for each zone - this is typically called S Plan Plus. Older systems simply have the boiler and pump connected to SL (8 in the wiring centre), with only N and E permanently connected. As programmer terminal 1 has power, so does wiring centre terminal 7 which is connected to the valve grey wire. The white wire already has power via the room thermostat, and as power is applied to both grey and white, the valve moves to position A. 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 This results in a noticeable delay when switching on heating only, as the motor has to move the valve from B to A. This takes several seconds. Overview Video

These diagrams show a modern boiler where the boiler requires mains power all the time, with a separate wire used to activate the boiler and the pump connected directly to the boiler. 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. 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 The thermostat uses one wire to control the primary functions of your HVAC system, such as heating, cooling, and fan. See the diagram below for the role of each wire in your system:Here the motor will move to position A (heating only). When it gets there, an internal switch connects white and orange together, and this output is used to activate the boiler. If the switch in the valve fails, the orange wire will never be connected to power. This results in heating only not working at all, yet the system works fine with water only or heating and water. Radiators never heat up, regardless of other settings. If your O or B terminal shares a label with another wire — typically W —identify whether you have a heat pump system or not. A heat pump runs your compressor for both heating and cooling. If you don’t know your system type, place this wire in the W terminal. If you have a heat pump system, put it in the O/B terminal. 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.