I bought my wmr200a from explora store. After getting 2 sensors from them that didn't work, they told my to send back the sensors and main consul. They confirmed a sensor was bad. They got the thing to work at their place and sent it back to me. Will be here on 3-10-09, in working condition. I should have put a mark on the main unit to see if it was switched out, but I didn't think of it. Don't you think they would expedite shipping but they did,'t. I just want the thing to work. The manufacture is worthless, had to deal with the seller. I was almost at the point of sending the whole thing back for a refund.I will let you know when I get the unit back if it works.