How much total water is in a hydronic heating system

ricking

I was calculating how much water is in my system (excluding the boiler) and was surprised how little there is. Then I thought maybe I am calculating it wrong.

I cant get an exact measurement on all the pipes, but I think I am pretty close. Around 450 feet of 3/8 copper in the ceiling.(Radiant) Around 125 feet of looks like 1 inch steel. I came out with about 8 gallons. Doesn't seem like much.

Mark Eatherton

http://www.engineeringtoolbox.com/pipe-water-content-volume-weight-d_1734.html

There are 7.5 gallons in a cubic foot, and 1728 cu. inches in a cubic foot..

Do the math

ME

ricking

I'm sure there is an easier way. Like volume a foot of pipe holds. Volume times feet of pipe. I was just surprised at the low result.

ricking

Actually that is the table I used. And after the "math", that's what I got. Just seemed low.

northernboiler

Here are charts:

dtrani

You probably aren't far off. Neither of the systems in my house will fill a 5-gallon bucket when fully drained (fin/tube baseboard).

DanHolohan

That's the beauty of modern hydronics. The pick-up factor for the early hot-water systems was 1.56. They lowered that to 1.33 in 19945, and then to the current 1.15 in 1967.

FranklinD

My converted gravity system with column radiators looks like it comes in around 82 gallons (radiators only). I have a good-sized mix of 3", 2", 1", and a lot of 3/4" steel pipe...for my purposes I came up with 100 gallons.

And as I type this, with the wind whipping from the NE off of Lake Superior at 10*, my average system water temp is 118*. They must have stuffed a ridiculous amount of cellulose in the walls back in the 90's.