I had a WF (WaterFurnace) E-series, 4 ton, closed loop system installed Jan. 2006 in new construction near Orwigsburg, PA. Water is public. There are 4 of us in the house. I have an instant (electric) WH that is fed from the 80 gal. tank the DSH is looped through. All of this is indoors in unconditioned basement. We use about 3500 gallons of water a month (About 1/2 of this is used for hot water?) There are 2 leaks inside the WF unit, in the copper piping going to DSH. We braised the first leak costing $200. A month later the piping leaks inside a "grey T" about 2 feet above the original leak. We turned DSH pump off and closed valves that feed it (as temporary or permanent fix). To replace the DSH the estimate is $700 after WF allowance. ----My question. How long will it take to get back the $700 cost. WF offered 15% off a new unit. I think it should be 75% off because I only used 25% of the probable life of the unit!!! Would complaining to BBB about the defects in workmanship do any good? THANKS!!