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Posted by HeatPro on April 07, 2011 at 15:39:17:
In Reply to: Re: triangle tube boiler and pump posted by Bisseti on April 06, 2011 at 22:39:41:
All circuits are less than 1 gpm and shorter than 235 feet of 3/4 tubing,
so
any circulator that can produce a 5 ft head (which is any residential circulator) can drive that (and actually 2 gpm) through 235 feet. Taco 007's are twice as powerful as necessary, but not a concern of overpowering.
http://www.taco-hvac.com/uploads/FileLibrary/100-1.8.pdf
The same Taco 007 will drive 7 gpm for 150,000 btuh through the 1-1/4 at 235 feet, so will do the job for the primary loop.
Taco ZRC's do well. Taco control boxes contain a transformer to drive zone valves.
The differential pressure bypass valve in the middle of the loop is there to provide the 5 feet of head differential from one side of the primary loop to the return side of the loop, so with one Taco 007 in the primary loop, you need no other circulators when using zone valves, other than the boiler circulator to get boiler water mixed into the primary loop.