I read Fuffy Bunny,s post about an un believable install he encountered. I ran into one last year and posted about it here but since reading his I will repost my experience. I am a retired hvac tech once owned the shop but is now run by son and grand son, I help out ocassionally when things get rushed. A year or so back we got a call after a heavy electrical storm stating that this homeowners power had been off and when restored his ac would not cool furnace blower would run but outside unit was dead. Day was a real scorcher temp near 100. Calls were coming in faster than they could be wrote up. I decided to take this call as it was near shop and homeowner said his wife had a broncial condition and the heat really bothered her. The timed fan control board was defective and after I replaced it ac took off. I stayed around a time and started to look over the setup. House was a 1400sq ft 2 1/2 story house with no insulation, the ac unit was a 4 ton unit, furnace was 100k btu.( much too large) The house had once been heated by a gravity furnace, it removed and replaced by the present Janitrol unit. The gravity furnace air intakes had been used for the return air system, a huge one was located in the kitchen right above furnace, the other was located at other end of house in living room. All the upstairs rooms had adjustable vents on the doors. The gravity setup had used 10 in piping with floor ducts. Someone had made funnel shaped adapters that reduced the gravity furnace 10 in pipe down to 6 in and some were connected to plenium by flex ducting, others by regular ducting pipe. Setup was reasonably quiet, did not short cycle and cooled place evenly and comfortably, I ask the home owner about his utility bills and they were surprisingly reasonable. Said furnace heated well and every place was comfortable. the systen was installed 20 years ago and has not given much problem beyond normal things that happen to hvac systems. Is the most cobbled up mess I have seen in my 60 yrs in this business, but it works surprisingly well. I guess this is just one of those setups where everything matched well enough to come out right.