One good indicator is looking at the boiler flame – which should be a healthy blue if it is yellow or orange then the boiler may not be getting enough gas, or conversely if it is getting too much gas, then this could be a more serious situation. Effective and environmentally friendly! Everything you need to know about business billing and charges. Please drop us a line below and we'll get in touch with you shortly! At help-link, we offer three of the most reliable and efficient brands.