I agree with Carl, I have a few TES824 installed(more or less the same as the Ta) and they are inexpensive and do what they say they will. the biggest problem is people installing them not knowing the limits of the system.
The problem here is not a huge one, and the customer will not even notice it after a while.
A person self installing one of these I do not blame for getting caught out, but someone selling this equipment without knowing what it can and can't do, should pay to put in something that will do it...
