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Posted by Heatpro on January 07, 2006 at 17:42:23:
In Reply to: Last Questions (hopefully)... posted by Bill on January 06, 2006 at 23:32:22:
: 1. Because of the physical layout of the piping, splitting the loop into two loops, with the additional 1 inch return piping (in the middle) will increase the total pipe circuits to about 250-270 feet (125-135 feet for each loop). This is still over the maximum piping for the pump (for each loop). Should I split the original loop into 3 loops, to keep them each under/at 100 feet?
+ The chart I directed to you is made to prevent plumbers from going too far with the loop lengths; however, there is some 'play' in the distance. A Taco 007 will move 12 gpm at a 7 foot head, so a little more distance will lower that flow rate to be more than needed for your required 8.5 GPM. In short, you can use just two loops with a maximum distance of each of 130 feet. The water of 8.5 gpm is splitting to two loops of 4.25 gpm, which 'fits' into the two loops at 130 feet each pushed by the Taco 007 which is moving the 8.5 gpm against a distance of 130 feet.
You can use the 1-inch trunk to both splits and probably have a 25 btuh drop across the circuit. If you want the max flow for two loops, use an 1-1/4 trunk instead, as that can handle 15 gpm through it and would compensate for the two 3/4 lines. It is a 'normal' practice to use a 1-1/4 trunk. What you will then have is this:
http://www.hydronicnetwork.net/hydronic/mulvalve/mulvalve.htm