What are the general guidelines for the installation of such devices with regards to fuel burning appliances? I am using two types of CO detectors. The system sensor COSMO and a stand alone device from interlogix (esl safe air 260-CO). The stand alone device's instructions say that they should be installed on the ceiling of rooms containing fuel burning appliances but not within ten feet of such appliances. The COSMO says not to install near furnaces etc. either. My problem is that the furnace rooms in this house are quite small so detectors can only be placed within a few feet of a fuel burning device.