Code for thermostat with 18b20

[Scampy]

Did you write the code, or is it cut and paste from some other example?

You need to post more details, hardware config etc. - There are other examples of reading multiple DS18B20's, but the one I use has individual pins for each sensor, rather then individually addressed on the one bus wire, and uses a case statement in the selection process. I also use DT's 18B20 include file which makes working with these sensors a lot simpler

SelectSensor:
  SELECT CASE Channel
    CASE 0 : @ DS1820_Select  _TempSensor1      ; Select the DS18x20 pin
    CASE 1 : @ DS1820_Select  _TempSensor2
    CASE 2 : @ DS1820_Select  _TempSensor3
    CASE 3 : @ DS1820_Select  _TempSensor4
  END SELECT  
RETURN