Why is the pump running constantly on a Greenstar CDi boiler?
The pumps on the Greenstar CDi range have a permanent live feed to them. If the pump is always running, there are generally 3 causes for this:
- The speed control wire (purple, white and black) going to the pump is damaged - check continuity and connection.
- The boiler has a weather compensating controller fitted (FW100 or Wave smart internet connected controller). The pump will run constantly to monitor the flow temperature and maintain heat curve.
- The PCB is faulty and telling the pump to run when it should not be running.