Thank you. What is "a substantial slug of off temperature water?" Do you mean off-temperature water?
If the valve is activated but not flowing, it cannot regulate the temperature. Let's say you have a color job to do and the jobo is fired up and at temperature while you load the tanks. How much time passes before the Jobo calls for that "tempered" water? OK, lets say 10 minutes. That 10 minutes, even if you have run the intellifaucet through the Jobo to stable, desired temperature, will allow the water in the line from the intellifaucent to the Jobo to cool down. This water, along with whatever water that flows through the valve in the 1 to 2 seconds it takes to achieve exact temperature, will enter your jobo tank. Depending on how far away from the valve you are and how insulated the supply line might be, you may inject enough off-spec temperature water to upset the process and cause color shifts.
While my 2200 has a function in the menu that will raise the tank and allow the tempered water to flow until you stop it, the amount of time the first developer runs will allow the line temperature to cool beyond the 1/2 degree tolerance required for proper development.
EDIT: Your 1500 does something similar too; from the manual:
4.2 Adjusting the water temperature
The water for the ATL-1500 is supplied by the tempered water inlet connected to the rear of the machine. The temperature of this incoming water must be adjusted with an external mixing valve. Water Mixing Panel II #4190 was made specifically for the ATL-1500.
The incoming water must be within ± 0.5ºC (0.9ºF) of the process temperature. To test the temperature, lift the top cover (#11), remove the tank from the trough (if loaded), lift up the rinse-water hose (#22), point the hose into the water bath, and press the RINSE button (#7). Use a thermometer to measure the temperature.
Its been a while since I have used this. Here is my plan; Comment if you can.
I have a diverter (Y), each output has a on/off ball valve--one part of the Y goes to a hose to the sink; the other goes straight into the ATL-1500. I was going to set the Intellifaucet to a few degrees to the process temperature since the ATL has a heater.
Whatever is in the line between the Y and the Jobo should be purged prior to starting the run and you should be fine, I would guess. I am going to heavily insulate these lines to minimize temperature drop.
The last question: Do you just turn off the output valves to the Itellifaucent and leave the power on to the Itellifaucet or is it better to turn off the input valves to the Intellifaucet and unplug it? I am going to call Hass on Monday and get their thoughts. I wasn't sure if water pressure and power on nearly all of the time would diminish its lifetime as I don't develop all of the time.
Thank you, Kino/others.
After everything is done, all cleaning and such, I turn off the main water supply valves, both hot and cold. I then open the tempered water to purge any pressure on the valve and cycle my D250 Intellifaucent from coldest to most hot temperature before turning it to the off position to assure the lines have depressurized. Not sure if iI will then unplug the unit, but probably will to avoid any possible circuit issues in case of some power spike or such...
I then open the darkroom sink lines to totally remove pressure from all water lines.
Finally, I open the Jobo tempering jacket valve to drain totally and activate one of the washing routines to relieve any pressure that might be on the input lines of the jobo.
I don't want any pressure anywhere in the system when the darkroom is not in use.