I'm pondering pipes from the near-boiler piping to the expansion tank.
I've poured over Siegenthaler and find no guidance there. It's common to see the little blue tanks hanging by their 1/2" pipe connectors. But you get into the spec sheets for the larger tanks like you will see used for systems with large heat storage tanks and the connectors are larger, up to 1-1/4" for Amtrol's SX160.
My puzzle is that even with a total system volume of more than 1000 gallons, if it is heating and cooling over a range of 100F from min to max over the several hours of the typical burn, the flow rate of the expanding water will only be something on the order of a small fraction of a gallon/hour. That flow rate wouldn't develop any appreciable head through 1/2" pipe, even if the expansion tank were 50ft. away.
So why do the larger tanks, which are usually installed in the same room as the boiler, have the large connections? Is it that these tanks are usually used with commercial systems and commercial guys don't use "weeny" little stuff like 1/2" pipes? Or is there a real need for larger pipes to larger tanks for some other reason than normal flow restriction?
And while everyone is so wound up about this question, what effect would you experience if the pipes to the expansion tank are too small?
The only situation I can imagine is, when the circulator kicks on, if it couldn't draw water out of the expansion tank easily it would have a harder time starting water to flow and that might cause a more noticeable pressure drop of short duration. Does that happen? Is it an issue under normal circumstances?
This is aimed primarily at the pros around here, but I welcome speculation from you all. That's half the fun on this forum, isn't it?
I've poured over Siegenthaler and find no guidance there. It's common to see the little blue tanks hanging by their 1/2" pipe connectors. But you get into the spec sheets for the larger tanks like you will see used for systems with large heat storage tanks and the connectors are larger, up to 1-1/4" for Amtrol's SX160.
My puzzle is that even with a total system volume of more than 1000 gallons, if it is heating and cooling over a range of 100F from min to max over the several hours of the typical burn, the flow rate of the expanding water will only be something on the order of a small fraction of a gallon/hour. That flow rate wouldn't develop any appreciable head through 1/2" pipe, even if the expansion tank were 50ft. away.
So why do the larger tanks, which are usually installed in the same room as the boiler, have the large connections? Is it that these tanks are usually used with commercial systems and commercial guys don't use "weeny" little stuff like 1/2" pipes? Or is there a real need for larger pipes to larger tanks for some other reason than normal flow restriction?
And while everyone is so wound up about this question, what effect would you experience if the pipes to the expansion tank are too small?
The only situation I can imagine is, when the circulator kicks on, if it couldn't draw water out of the expansion tank easily it would have a harder time starting water to flow and that might cause a more noticeable pressure drop of short duration. Does that happen? Is it an issue under normal circumstances?
This is aimed primarily at the pros around here, but I welcome speculation from you all. That's half the fun on this forum, isn't it?