Boiler combi 1.5 bar at moment, impellor fine and oump

get a gas safe engineer to check it.

Pressure: The normal operating pressure for a combi boiler is typically around 1 to 1.5 bar. If the pressure is too high, it can cause issues with the boiler. In your case, the pressure seems to be at 2.5 bar, which is higher than the recommended range. You can try bleeding some water from the system to lower the pressure back to the normal range. Air in the system: The sound you described, like air in the flue or drinking through a straw, could indicate the presence of air in the system. This can prevent the boiler from firing up properly. You might need to bleed the radiators to remove any trapped air. Check your boiler's manual for instructions on how to do this. Flame failure: The red light with a flame symbol and a cross through it suggests that the boiler is not detecting a flame. This can be caused by various factors, such as a faulty thermocouple or a blocked burner. Pushing the red button might have reset the boiler temporarily, but the underlying issue needs to be addressed. It's best to contact a qualified heating engineer to inspect and repair the boiler. Strange noises: Unusual noises coming from the boiler could indicate a problem with the pump, motor, or other internal components. It's important to have a professional take a look at the boiler to diagnose and resolve the issue. In any case, it's recommended to contact a qualified heating engineer or boiler technician to assess the situation and perform the necessary repairs. They will have the expertise to identify and fix the problem with your boiler safely.

Firstly find out what the make and model of the boiler, then I would recommend that you speck to the technical department, they will advise you what the fault is , then I would recommend calling a registered technician that deals with your boiler hopefully this will help you.

This needs a gas engineer to check. Please don’t attempt unless you are gas safe registered.