Just installed Omnistat2 thermostat but I get a error message "outside sensor fault". I don't have a outdoor sensor but is there away to get around not using a sensor & if you can't can you use a Model 31a00-7 extended range temp. sensor? Also can't figure out why my thermostat isn't talking to my controler Omni LT. I use serial from my computor to controller and then a three wire to my thermostat. Not sure, must be maybe Communications Mode settings. I went with 9600 system Baud & 9600 with expansion baud. I have a heat pump single stage cool & three stage heat. Have furnace with electric heat back up. Of course my heat pump is locked out and running with back up heat now. Any suggestions? I'm getting a refrigeration teck. to come in to look at it but he might not know some of the HAI configurations. Thanks