We recommend that you do not run water pumps that used brushed DC motors from the fan outputs. This is because the starting current for a brushed DC motor is usually many times the running current, and will probably exceed the 4.4A rated current of the bed mosfet.
If your E1 Heat output is free then you can use that to drive the water pump; but then you must use an external flyback diode.
Maybe add that to the warning about adding diodes to brushed motors in the wiki for completeness? (And good catch!)