We have recently (Oct) fitted 7 IR heaters which use triac based controllers. There have been any number of problems with the controllers and IR halogen elements failing. The supplier has now suggested that we may have interference or spikes on our mains supply which they claim may affect or even cause the controllers to fail! The heaters are on a separate new ring main. We do have some older fans for an oil heater on a separate ring main and a oil pump and water pumps on systems fitted in 1989 and which are on yet another ring main Is this a reasonable possibility as an explanation? And if it is a problem what can be done?