Loop Sizing

[tbolt]

I know it depends on what type of soil you have, but is there a rule of thumb for how long the poly pipe in the ground should be on a horiz closed loop system and how many loops you can put in one trench. I'm quoting a 4 ton system and have handled the equipment, pumps, ductwork etc but for my own education would like more info on the horiz loops

[hvacmontana]

A very basic rule of thumb would be 500' of pipe in an extended slinky laying flat in a trench 8' deep for each ton of heat pump capacity. Space between loops at least 2'-3'. A 4ton system would use a trench approx 100' long by 25' wide and 8' deep.

[aaronforprez]

if i have room, i have done 700 foot rolls of pipe, going 350' out and 350' back spacing the lines 1' apart in the trench. so a 4 ton system, 8 lines, 7 foot wide trench, 350' out.

slinky action - 800 foot loops put together on 18" spacing, 36" wide, creating a 95' loop. we space the slinkies 2' apart. occasionally what we will do is drop every other slinky 3' deeper in the ground and then dig the trench 12' wide rather than digging a trench 16' wide. this works real well on a 3 ton system. the trench has a shelf on each side with a 3' deep trench through the middle. trench depth depends on when we find moisture in the ground on a 12 ton system we did last spring we went 12 - 15 feet deep b/c it was extremely sandy and we didn't hit nice moisture unti 10-15 feet. that was an exception to the rule for us as we usually go 7' deep.

every situation is different.

[weber]

You should post this in the pro forum for more technical responses.