Information on dealing with wastewater issues and emergencies. Very professional alex got the job done! would definately recommend to others who are in need of plumbing services. The root of the problem comes from the boiler overheating the. To ensure that your combi boiler is working properly, you need good mains pressure if you are having a new boiler fitted, you should check what the mains pressure in your area is before you go ahead with the installation. The baxi duo-tec.