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# Glycol Calculations

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Member Posts: 27
I am trying to find a simple formula to calculate the amount of glycol in a heating system.
My customer has 3300' of 5/8" oxy tubing, 12' of 2" copper with a number#30 expansion tank.
Glycol will be 50%.
Does anyone have a simple calculator available?
Jeff

• Member Posts: 22,491
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What about the boiler capacity, it could be the largest number?

35-n40% is usually adequate, unless you expect -50 below inside

Glycol doesn't transfer heat as well as water and requires more pumping power, as well a fluid maintenance.

Select a top brand\$\$ with good inhibitors and blend to a reasonable protection %.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 903
edited October 2018
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no idea on tank.
But just because it's interesting to see the numbers on long tubing .....

Tubing Volumne = length x cross section area ( using ID)
1728 cubic inches = 1 cubic foot = ~7.48 gal
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3300' of 5/8" oxy tubing ..... assuming it's 1/2 ID that internal volume is:
77715 inch^3 = 4.497 ft^3 = 33.6 gallons .
I don't know oxy tubing.....Measure ID of your tubing.
If it's 5/8 inch ID then it's 52.5 gal

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12' of 2" copper...... assuming it's 2 inch ID that internal volumne is:
452 in^3 = 0.26 ft^3 = ~1.96 gallons

• Member Posts: 15,844
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I get 35.6 gallons of system capacity plus your boiler or heat exchanger. You can find their volume from the manufacturer.

So far 35.6 x .5=17.8 gallons @50% glycol.

Their is no calculator it's all math
• Member Posts: 1,959
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My calculator says 44.22 gallons in 3300ft of 5/8" PEX and 1.93 gallons for 12ft of 2" type L. A #30 Amtrol holds about 2.25 gallons. So my total says 48.4 gallons, plus boiler or exchanger. I assume you'll have some other piping, pump, manifolds, etc to figure in as well
• Member Posts: 22,491
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Use the commercial sizer program at Amtrol, it allows for glycol %, as that will change tank size.

amtrol expansion tank sizer
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream