If the boiler pressure is too high, it can lead to a number of potential issues, including:
 
Increased risk of boiler failure: High pressure can put excessive strain on the boiler's components, potentially leading to leaks, cracks, or other damage that can result in a boiler breakdown.
 
Reduced efficiency: High pressure can cause the boiler to work harder than necessary, leading to increased energy consumption and higher operating costs.
 
Safety hazards: Excessively high pressure can pose a safety risk, as it can cause the boiler to overheat or even explode in extreme cases.
 
Water leaks: High pressure can cause the pressure relief valve to open, releasing water and causing leaks in the boiler system.
 
Damage to other components: High pressure can also damage other components of the heating system, such as pipes, radiators, and valves.
 
To prevent these issues, it is important to regularly monitor and adjust the boiler pressure to ensure it stays within the recommended range. If the pressure is too high, it may be necessary to bleed the system or adjust the pressure relief valve to bring it back to a safe level. If you are unsure how to do this, it is recommended to contact a professional boiler technician for assistance.