Latest wiring diagram for a combi boiler - Maximum programmers suit onto a fashionable backplate, which has l,n,e and 4 numbered terminals. Whilst the plate is bodily same, the wiring may not be. Always take a look at the wiring cautiously while replacing any programmer - assuming it's miles the equal can without difficulty cause harm and destruction. This is the equal switching arrangement, however here a three wire thermostat is used, which requires a impartial connection. Right here, the impartial is shown from the boiler, but it may be furnished through the programmer if that is more convenient.
In this arrangement, electricity is furnished to the boiler and programmer through the 3a fused spur. Terminal 2 of the programmer is permanently linked to line. With the programmer on, terminal four is also related to line. If the thermostat is likewise activated, the sl terminal at the boiler is attached to line, and the boiler operates. A extensive variety of programmers and timers is available, however they all work inside the identical way - a pair of terminals is connected collectively whilst the tool is ready to on. The example here indicates the transfer among terminals 2 and four, however this could vary. Usually check the commands supplied with a programmer.
The diagram suggests a standard programmer. In this layout, the terminals 2 and four are related together whilst the programmer is on. The programmer requires a permanent mains deliver which need to be taken from the boiler terminals. This ensures the whole system can be remoted the use of the three amp fused spur. Some programmers, especially older ones, have a permanent link between line and the commonplace terminal (2 in those examples). At the same time as that is convenient for mains structures, it does imply the programmer can't be used for volt-loose switching.
So as to work nicely, the programmer and thermostat must be wired in series. For volt loose switching, the circuit begins on the boiler terminals, passes thru the programmer, then through the thermostat, and returns to the boiler. The boiler will handiest perform when each the programmer and thermostat are on.