As a Heating engineer i fit only WB Boilers and this is a common fault with the DT20RF. I was on a WB training course a few weeks ago, where i was also asked about most common faults. This was one many plumber where asking about. I asked if i could overcome this and the answer was basically a no. Wireless sounds great, but it's more trouble than it's worth. So I'm back to using hard wired Roomstats. Ever customer's house that reported this problem had a wireless router for internet use, near by. An if it wasn't in my customers house it was next door. For anybody that has had this DT20RadioFrequancy installed and have the same problems, i suggest you ask the installer to fit a DT20 Wired. A good plumber will do this if you explain the above, Regards
J.R Bennett
April 2011