I have built a house at the Esplanade Brighton and

I have built a house at the Esplanade Brighton and had a ART 45LUAK ducted invertor system fitted. Presently we have had 7 days over 35 degrees with a week of the high 30's to come. The first time we used the unit the ceiling flooded with water pouring through down lights, sensors, and switches together with soakage in the kitchen ceiling. I contacted the installers who said it is the plumbers fault. The plumber stated he wasn't contracted to do the job - he was working for my builder in other capacities but plumbed it to the outlet where the flexible pipe was pulled through the wall. He did it as a favour as the installers had no intention of coming back in the near future due to the volume of work. Where the a/c installers left the overflow pipe was 300mm below the outlet to waste. I got sick of the run around so one of my managers and myself carried out a test which proved that the overflow water wouldn't flow more than 15mm uphill to waste hence the flooding. To achieve proper removal of the overflow water means pulling kitchen cupboards apart and chasing the pipe up the cavity to bring it out at a slight run off to the waste. It also suggests without doubt that the unit wasn't test run with the waste in place. Please advise. Peter K. Swaffer