I've got an MPH2 unit that acts like it's faulting out at the top floor. It's a 2 stop unit and acts fine except that it won't run down from 2 on normal. I can run it down on inspection no problem. I checked the HU HD LU & LD sensors, the bottom directionals, made sure the traveler, replaced the floor control board, the IO board in the controller and the main board with the ice cube relays on it I'm not sure if this thing lost it's parameters or what. There was a 9V battery that was. dead when we took the job over that was replaced. Thanks in advanced for the help.

Do you have an HHT?

No I was thinking about ordering one from world electronics. We only have 2 of these units under service but I think that tool is good for other units as well.