The main controller was replaced by Honeywell. This was before the present problem. I have replaced the main controller myself (another 70 quid) but the same result. So this is the second replacement controller.
Where are these relay circuits? are they in the HC60NG or in the ST9400C controller?
Having replaced the ST9400C twice and the HC60NG once, I am quite puzzled.
Could the PC wireless or the Panasonic cordless phone (both may yards away) be doing it? altho they are all on very different frequencies....