# Thread: Liquid Line Lift loss -vs- tonnage

1. I usually work on larger equip but was wondering if LL lift and friction can have a different effect on a smaller unit than it would have on a lager one. Let's say I've got an AHU 60' away horizontally and 25' up. I think a 10 ton unit would have no problem but what about 1 1/2 ton unit? I know pressure is pressure but what about the percentages?

2. Professional Member
Join Date
Nov 2002
Location
emerald city, sc
Posts
1,469
Post Likes
the size of the liquid line has more to do with it, than the size of the unit.

3. Banned
Join Date
Feb 2005
Posts
1,475
Post Likes
Those factors are more critical to the suction line than the liquid line, assuming that they are taking the same route, but whatever you are working on you find the Mfrg. literature on it and see what they recommend.

4. Originally posted by incontrol
I usually work on larger equip but was wondering if LL lift and friction can have a different effect on a smaller unit than it would have on a lager one.
Liquid line loss due to vertical lift is simply due to the density of the refrigerant. Density in lb/ft3 times lift in feet divided by 144 in2/ft2 gets you pressure loss in psi. For example, R-22 saturated liquid at 100°F has a density of 71 lb/ft3. A 10 foot lift gives us 71 * 10 / 144 = 4.9 psi loss. A good rule of thumb to use with most refrigerants is 0.5 psi loss per vertical foot.

Liquid line loss due to friction is a function of your liquid line size.

5. Originally posted by incontrol
Let's say I've got an AHU 60' away horizontally and 25' up.
Lets just hope its not a heat pump.

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•

## Related Forums

The place where Electrical professionals meet.