Bit the bullet and removed the maintenance nightmare vacuflush system. Replaced the restricted outlet closet flange, 1 1/2" piping, pump and tank with 3" (2-elbows & 1-ft. of pipe) into the top of the holding tank. Fooled the controller with a jumper wire into thinking the vacuum switch is satisfied and all works good so far. No more worries about the compartment getting flooded with you know what when the pump diaphragm ruptures.
