Where Does Carbon Monoxide Come From? When a fuel is burned, carbon monoxide is created. Your boiler and water heater create this gas as a product of combustion. It's vitally important to check the venting of your boiler and ALWAYS keep a carbon monoxide alarm next to your boiler and water heater. This is no [...]The post Carbon Monoxide Awareness: A look from the field appeared first on Cahill Plumbing & Heating: Westborough Plumber (508) 366-9220.