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View Full Version : coil sizing - custom project..



cadillackid
24-04-2010, 07:57 PM
ok time to play... I came upon a bunch Split kit.. 10 outdoor units and 8 indoor units.. now there's a catch...

the building had a fire... 2 of the indoor units are scrap.. melted and burned up... the other 8 indoor units were smoked good but the heat and fire and for the most part the water stayed away from them....

of course they are not usable because of the plastic being smelly and discolored.. the insurance company came, looked at them all and said "scrap em".. so somehow i ended up with them... most of them are a year old or less...

now onto my project.. i thought i would experiment with a couple of them..

as you guys know I created a custom installation in my home using Mini's fitted to my ductwork with custom computer programming and the like...

so i thought.. hmmm wonder if I can use the electronics from a mini and use a standard Box coil rated for 410A heatpump and fit them to a ducted system.....

so I ripped apart one of the indoor units.. the original evaporator coil is a standard 3 fold "Multi-fold" coil found in most mini's....

it uses a 3/8 x 5/8 lineset...

the original coil has 4 feeders distributing the refrigerant.. ..

the coil contains 34 tubes of 5/16" OD thinwall pipe (1/4" ID)...at 35 inches length. scary for R410A if you ask me...

the unit is rated 5000 to 23,500 BTUh MAX in cooling (it is sold as a 1.5 ton inverter)

and 5600 to 25,400 BTUh MAX in heating...

so my question is if i am going to use a different coil, do I want to size the new coil on refrigerant Tube Volume or do I simply want to look for a new coil that is rated for say 1.5 to 2 tons?

I figure I will have to calculate tube volume to help determine the refrigerant charge.. the systems uses EEV's so its going to be near impossible to charge with Gauges..

do I want to add refrigerant volume based on a coil that is 50% liquid? meaning 1/2 the additional volume?

or is there a better way to calculate?
-Christopher