Troubleshooting common boiler problems
If You Have A Boiler that Fires Continuously
A usual cause is a faulty thermostat. This generally requires a thermostat repair or replacement.
There could also be a wiring fault that could need a repair.
One more possibility is a is faulty or sticking control valve which needs Replacement.
If your Boiler Overheats and Is Noisy
It could be due to poor primary circuit circulation. Venting the system should resolve this.
Another possibility is low shunt-pump discharge pressure, because of an obstruction in the piping;
Possibly due to an air pocket in the line; this requires purging the system.