With all contemporary machines, the dialysate concentrate is fed into the machine, water is fed from a water tank and a marvelous pump mixes them to the desired concentration.
However, in many centers all machines are set to the same temperature, and in many cases it is too cold, in addition to the freezing air-condition.
To remove air from the blood lines and dialyzer, the machine should run for a few minutes with the dialyzer mounted upside down, that is, the red header is down and the blue one is up.