Serving new haven & fairfield counties in ct. Ensure your gutters are regularly cleared. However, if you do have a pilot light, it should always burn with a bright, solid blue flame this shows that the boiler is burning efficiently and correctly if your pilot light burns with a yellow or orange wavy flame, the gas is not burning cleanly and this could be a sign of a carbon monoxide leak. We've got a new combi (about 2 weeks old!) my parents have an old one and have to wait quite.