Hi there
Not sure if this is any good but have you followed the installation instructions to the letter. Have you started with a vertical lift not more than 30cm from the unit? Does any horizontal runs flow to the stack as a normal drain (gravity)?. If this is correct, is the valve on the...
When fitting saniflo's due to the run off the discharge there is a tendency to syphon. It tells you this in the manual. You can fit an anti-syphon valve to the discharge pipe. See installation advice on saniflo's web site (Not direct fall) :wink: