There was a fault with a batch of valves about 18 months ago, but this has been resolved, if this was a turn key jet, did they not check that it all worked before giving it too you? does not sound very turn key to me.

On thing you can try is to reset the valve first, you do this by holding down both buttons and then powering up the valve, I have found that I did not need to set anything else in the valve after that it all worked fine, long progressive braking and held air before and after brake application.

Mike