What causes the combustion engine overheat during the operation of the gas-fired boiler?

Question details (performance):

The boiler is overheating in operation.

Answer: Fault reason:

1. High cycle resistance of the system (blocked).

2. The overheating sensor is defective or disconnected.

3. Water pump does not circulate or impeller is plugged.

Troubleshooting:

1. Confirm pipe and valve are reliable.

2. Confirm point of discharge and adjust or replace igniter.

3. Replace the main controller.