The ATL-1000 requires a tempered water supply. It is designed to operate with one. However, you are correct that with the B&W programs, the machine itself does no tempering -- it only does that in the color programs, where it tempers to 100 deg F. If you have a tempered supply -- usually just a mixing valve with a thermometer built in -- this is really no problem. You just mix up the developer at 20 deg C and set the tempered supply to 20 deg C so the water in the trough is that temperature and away you go. Bottom line, there is nothing wrong with your machine -- that is the way it is supposed to work.