Cook DB inline fan under performing

[Paulinator]

For some LEED projects that i have been documenting we have DX cooled AHU's with remote condensers.

In order to document the LEED credit i need to know the refrigerant charge in the system. The condensing units need to be field charged with R-134a. Supplier told me roughly 1 lb per ton of cooling.

Is there any way to find out refrigerant charge without busting some serious thermodynamics and tracing the length of piping??? IF i need to bust out some thermo anybody wanna point me in the right direction?

[lwarren]

That 1lb per ton estimate can vary greatly with the size and length of your line sets.
Most manufacturers provide a charging chart for line sets beyond the standard 15 -25 feet range. So if you can get the IOM for the unit and the length of your line sets you should be able to get real close.

If these units are already running the person(s) who started them should have the documentation to show the charge.