The CAP 40 is built to use 2 liter chemistry kits. You can process 32 8x10 photos, or the equivalent number of square inches of print material with each kit.
In practice, you need to do test prints for the first 3-4 prints as the developer needs some silver in it to work correctly. You can then make display prints until about print 22-24 where there will begin to be a bit of color crossover in the shadows towards red. At that point, you need to start making test prints for the next run of display prints.
Chemicals will keep overnight in the processor, but you don't want to leave them for more than about 36 hours or the developer will oxidize.
There are two types of "turbulator plates." A turbulator plate is the cover over the chemical tank. The chemicals are pumped through a stainless tube at the back of the plate toward the front of the plate where it runs over the edge and back into the tank. They provide a laminar flow of chemicals over which the paper is passed as it is transported through the machine.
The first type of turbulator plate has small pins that stick up about 1/4-inch. The second type of turbulator plate is stepped. The plates with the pins can cause an uneven development pattern. This is noticed as parallel streaks in areas of solid color. It is most noticable in areas that are lighter or near white. The stepped turbulator plates were introduced to eliminate this problem.
A well used CAP 40 will have silver plating in the developer tank, on the developer turbulator plate and on the transport roller at the rear of the development tank. This is normal. It looks like a silver gray film on the surfaces.
The machines are quite easy to clean. Drain the chemistry and replace it with hot water. Run the machine for about 20 minutes with water and drain the machine. Take the turbulator plates our and rinse them and set them aside to dry. Remove the rollers and rinse them and dry them. Lastly, rinse out the tanks one more time and it's clean.
The concerns with the machine are: does the heater work? Do the pumps work? Do any of the rollers have flat spots?