Our central heating system had died (the boiler ripped open). Therefore we needed to buy a new one. But the problem was that the new models could only drive 1 pump (unless you buy a very expensive model).
We have 2 zones that are heated separately, so 2 pumps are used. I designed a circuit that receives the 2 signals from the thermostats and combines them to 1 signal to ignite the burner. From the burner there is a signal that tells a pump to work. I connect that signal to my pcb to drive 1 of the 2 pumps. This heater also has a function to let the pump work for a while after the thermostat switches out. So the circuit remembers witch thermostat was on last and leaves the pump on as long as the burner wants.
To build for the future I’ve made the print for 3 zones and placed a header to connect a 433Mhz receiver for a wireless thermostat. The code for this is not ready but the hardware is.
The circuit: |
The pcb layout: |
Pictures:
Connections:
Dutch 
