There are several potential reasons why your radiant heating system may not be working. One possibility is that the system is not properly installed. Another possibility is that there is a problem with the thermostat or with the valves that control the flow of hot water through the system. A third possibility is that there is a problem with the boiler or with the piping in your home. If you are unsure what might be causing the problem, it might be best to consult a professional to diagnose and fix the issue.

Most likely, the cause of your radiant heating system not working is that there is something obstructing the flow of heat from the floor to the room. This obstruction could be something as simple as a layer of dust or dirt on the floor, or it could be a more serious problem such as a hole in the ductwork. If you're unsure what might be causing the problem, it's best to call in a professional to take a look at things and diagnose the issue. In some cases, it may be necessary to replace certain parts of the system in order to get it up and running again.