You will also need some connection to terminals 2 and 5 as these are the supplies to the programmer’s internal hot water and central heating switches. Furthermore, the Horstmann 425 Coronet supports multi-zone control, making it suitable for larger buildings with multiple heating zones. This feature enables independent temperature regulation in different areas, providing personalized comfort and reducing energy consumption. If your system’s control components are 230V, then the live terminal should also be linked to terminals 2 and 5. Did you remove any links whe you moved the programmer? Hot water 'off' (Switched live to 'satisfied' at hot water cylinder thermostat and motorised valve grey wire) the Boiler is about 30yrs old. very simple and nothing to breakdown and never did. heats up water in one circuit to serve emersion tank & c/heating.

It's difficult to see what wires are in some of the terminals due to the angle of the photo, and it will be a bit of a guess as to where each of them go at the other end, because it's down to the installer’s preference and method of installation. So, if any of my assumptions are wrong, please say so. The durability and reliability of the Horstmann 425 Coronet are ensured by its high-quality construction and materials. It is designed to withstand daily usage and operate efficiently over time, offering long-lasting performance. I wonder if anyone is able to help. I have a ServoWarm Elite 50 Boiler . it is over 30 years old , and is extremely reliable and has never really broken down. This is a simple hot water boiler system . with a pump and thermostat all in the housing. there is no room thermostat. so all it does is, send hot water around in a single circuit serving the emersion tank and central heating. The boiler thermostat is controlled by the max//min settings in the honeywell modulec unit and when hot enough the boiler turns off, and on again etc until the timer goes off. then the pump overrun continues for a little while. The Horstmann 425 Coronet thermostat is a device used for controlling and regulating heating systems in residential and commercial buildings. Specifically designed for the US market, this thermostat offers advanced functionality and ease of use.The puzzle here is that without an input on terminal 2, there is no way terminal 1 (hot water on) could become energised when the programmer switches 'on' the hot water, yet you say it’s working? Equipped with advanced technology, the Horstmann 425 Coronet offers various features to enhance heating control. These include programmable scheduling, allowing users to set different temperatures throughout the day to suit their needs. It also includes a vacation mode, enabling users to lower the temperature when away from home without affecting overall system settings. yes i am trying to replace this with an external or any timer that works, and we are discussing about how to get around the pump over run problem