near-boiler piping on gravity conversion

Mark J Strawcutter

My understanding is that reducing the size of near-boiler piping on a gravity conversion to forced circulation is to provide enough pressure drop to satisfy the head requirements of the circulator.

Since this is usually a function of pipe size and length, and since such a short lenght of pipe is involved, I also suspect that the rule-of-thumb for "half the size of the mains then drop one size" intentionally produces a much smaller pipe size than would "normally" be used.

If my assumptions/understanding are/is indeed correct, would it not also be possible to achieve the same goal with a [partially closed] balancing valve in larger piping?

Mark

kevin

near boiler piping

I did something like that before on a boiler/gravity conv. It was only after that I read "How come" Dan has an excerpt on the heating Q&A section of this website.
The ball valve closing would work, but why spend the xtra money on bigger pipes and valves, unless its already done... kpc