10
3000
1/2
5/8
5/8
5/8
1/2
5/8
5/8
7/8
5/8
5/8
7/8
7/8
3/8
3/8
3/8
3/8
4000
1/2
5/8
5/8
5/8
5/8
5/8
7/8
7/8
5/8
5/8
7/8
7/8
3/8
3/8
3/8
3/8
6000
5/8
7/8
7/8
7/8
5/8
7/8
7/8
7/8
7/8
7/8
1 1/8
1 1/8
3/8
3/8
3/8
3/8
9000
5/8
7/8
7/8
1 1/8
7/8
7/8
7/8
1 1/8
7/8
7/8
1 1/8
1 1/8
3/8
3/8
3/8
3/8
12000
7/8
7/8
1 1/8
1 1/8
7/8
7/8
1 1/8
1 1/8
1 1/8
7/8
1 3/8
1 3/8
3/8
3/8
3/8
3/8
15000
7/8
1 1/8
1 1/8
1 1/8
7/8
1 1/8
1 1/8
1 1/8
1 1/8
1 1/8
1 3/8
1 3/8
3/8
3/8
3/8
1/2
18000
7/8
1 1/8
1 1/8
1 3/8
7/8
1 1/8
1 1/8
1 3/8
1 1/8
1 1/8
1 3/8
1 3/8
3/8
3/8
1/2
1/2
24000
1 1/8
1 1/8
1 1/8
1 3/8
1 1/8
1 1/8
1 3/8
1 3/8
1 1/8
1 1/8
1 5/8
1 5/8
3/8
1/2
1/2
1/2
30000
1 1/8
1 1/8
1 3/8
1 3/8
1 1/8
1 3/8
1 3/8
1 3/8
1 1/8
1 3/8
1 5/8
1 5/8
1/2
1/2
1/2
5/8
36000
1 1/8
1 3/8
1 3/8
1 5/8
1 3/8
1 3/8
1 3/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1/2
1/2
1/2
5/8
42000
1 3/8
1 3/8
1 3/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1/2
1/2
5/8
5/8
48000
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1/2
1/2
5/8
5/8
54000
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1/2
1/2
5/8
5/8
60000
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1/2
1/2
5/8
5/8
66000
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1 3/8
1 3/8
1 5/8
1 5/8
1/2
1/2
5/8
5/8
1. All line size are basic for O.D type L copper tube. The above table is maximum suction size and riser size should
not exceed horizontal size.
2. Suction line size should be selected at pressure drop equivalent to 2 F, and reduce estimate of system capacity
accordingly.
3. For easy oil return, use U trap in suction line.
4. Consider double suction risers, if capacity control can reduce capacity 35
%
below.
DEFROST
Once ice forms in an evaporator coil it keeps building more ice and eventually will lead to equipment
failure if not manually defrosted.
Some symptoms of ice forming in the coil are:
1.
loss of air circulation and air throw
2.
loss of room temperature.
3.
no off-cycle time.
4.
flood back.
5.
water spitting out of the fans or coil on air defrost systems.
Long term ice formation will crush the refrigerant tubes in the coil causing leaks and major equipment
problems. If ice formation is suspected, carefully check the interior rows of the coil with a good light. Ice
formation usually starts at the bottom of the coil in the middle rows and can be difficult to detect.
For most applications, two to four defrost cycles per day should be adequate. The defrost requirements
will vary on each installation so the defrost settings should be determined by observing the system
operation.
Air defrost
The normal “off cycle” of the compressor may be
adequate to keep the evaporator coil clear of frost.
In other applications, a defrost timer may be
necessary to help assure a clear coil in a medium
temperature environment, “Air defrost” is
initiated by the timer, but the evaporator fans
