[an error occurred while processing this directive]
Posted by Heatpro on December 09, 2005 at 11:17:43:
In Reply to: Final question on Spirotop posted by Dave on December 09, 2005 at 10:47:32:
Too much thinking. The thought incorporates a 'magic' that any moving water 'pulls' air to it and gathers air to move it where the motion is.
Actually in a 1-1/2-inch pipe, the suction is local to the branch of the tee going to the zone, not in the main body of the 1-1/2-inch pipe.
If what you are thinking were true, the air scoop idea wouldn't work as a 2-inch body spirovent chamber would draw all the air past the top of the vent body to have it eternally go out the side branch to the system. Also the high-spot of an air scoop would suck air from the chamber above to the system, especially with all 24 gpm going through.
Also, an old-type expansion tank with no diaphragm wouldn't work because the water going past the tap where the tank was attached would suck air from it.
The concept also assumes that there will always be a zone running to suck all the air to it.
If you don't like the idea of a small chamber taking air from it, then the tank as an air scoop is the best location, as it makes the water the stillest at the widest point, the air vent on the vertical riser above it is the next stillest point.
If you are worried about the radiant zone drawing air, make sure that it is the bottom pipe off the branch; but it really isn't something to stay up nights for.