Had a customer that I installed a RB ESP Mi who kept getting fault light warnings and the message MV ERR. (He had no MV) In addition his seasonal adjust had single digits which could not be eliminated. (It's only meant to adjust in increments of 10%) Called RB and they said some controllers prior to July 07 had a soldering problem and return immediately for a refund or replacement. Replaced with WM smartline. Will sell customer weather monitor next service call.