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Old 03-01-10, 08:58 PM   #6
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Default Xringer's Daydream...

Originally Posted by [CENTER
Xringer[/CENTER];5896]Since the waste water is at near zero PSI, and I want keep the heat inside, and make it cheap.. How about using 2" or 3" PVC for the water-jacket?

I would attach a 2" PVC flex hose to my tub drain, connect it to the SWWHR
input and drop the waste output with another flex hose into the washing machine drain pipe.

The trick would be sealing the 1/2 copper cold water pipe (L type) in the center of the end caps. Since the gray water has such low pressure, it might not be a big problem. Perhaps the copper supply pipe need not be in the center.?. Maybe it can be positioned near the bottom of the PVC, to insure it's completely covered by the flowing waste water..

The PVC tube would be about 4 or 5 feet long and not quite level,
so it will fill up with gray water, before pouring out the higher end.
Insulate it well and start using less oil to heat my shower water!
This sounds like a great idea. I have the same problem with the waste line being too high to use the GTX configuration.

Some possible problems I can think of...

* Expansion differences between copper pipe & PVC could prove difficult to seal. Do you know what the thermal expansion index is of PVC & copper?

* A very good feature of the GTX configuration is that the waste water falls straight down and 'scours' the surface of the exchanger pipe. So, on a more horizontal configuration, you may want to allow for clean-out ports as are built into many ABS elbows & sink traps.

Overall, the PVC/copper combo could be a real cost-effective plan.


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