18
Enertech Global
IOM, BS/BT Models
Section 5: Line Set Installation
Equivalent Length
Each valve, fitting and bend contributes to friction
pressure drop because of the interruption of smooth
flow. Because it can be difficult to calculate the
pressure drop for each fitting and valve it is more
useful to equate the pressure drop to an equivalent
length of straight pipe for each fitting. This allows for
a quick calculation of the total equivalent length (see
Example 1).
The equivalent length of copper tubing for
commonly used fittings, valves, and filter-drier are
shown in Table 4.
Linear Length
The total length of liquid line or vapor line between
the condenser and evaporator.
Linear Liquid Lift
The sum of all vertical liquid lines.
(See figures 2 and 3)
Linear Vapor Rise
This is the sum of all vertical vapor lines.
Limitations are the same as linear liquid lift.
(See figures 2 and 3)
Maximum Pipe Lengths
Maximum Equivalent Length = 75 feet
Maximum Linear Length = 50 feet
Maximum Linear Liquid Lift (when air handler is
above compressor section) = 20 feet
Maximum Linear Liquid Lift (when compressor
section is above air handler) = 10 feet
Piping Limitations
Bi-flow liquid line solenoid valve and crankcase
heater are required when equivalent length is
greater than or equal to 50 feet or when 20 feet
of vertical separation is between the compressor
section and air handler.
Note:
The equivalent length of fittings and
accessories must be included to calculate the
overall equivalent length but not included to
figure out vertical liquid lift or vapor rise.
Table 4: Equivalent Lengths in Feet
Equivalent Length in Feet of Straight Pipe
For Valves, Fittings and Filter Driers
Line
Size
O.D.
In.
90°
Long
Radius
Elbow
45°
Long
Radius
Elbow
90°
Short
Radius
Elbow
45°
Short
Radius
Elbow
Liquid
Solenoid
Valve
Bi-Flow
Liquid
Filter
Drier
Bi-
Flow
3/8
0.8
0.3
1.2
0.5
6
1/2
0.9
0.4
1.4
0.6
12
5/8
1.0
0.5
1.5
0.8
3/4
1.3
0.6
2.0
0.9
7/8
1.5
0.7
2.3
1.1
1-1/8
1.8
0.9
2.7
1.4
Table 5: Long Line Set Parts
Crankcase Heater Information
Models
Part Numbers
Description
018-036
48P001-01NN
Crankcase Heater
048-072
48P002-01NN
Bi-Flow Solenoid Valve
Models
Part Numbers
Description
Models
018-072
ARS-4A
1/2” Valve Body
ARSCB
24V Coil
ARSBK
Bi-Flow Kit
All three bi-flow parts must be ordered for valve to be
installed properly.
Bi-Flow Liquid Line Solenoid Valve
In order to minimize off-cycle refrigerant migration
to the compressor, a Bi-flow liquid line solenoid
valve is required for all long line set heat pump
applications. The Bi-flow solenoid valve controls
the flow of refrigerant only in the direction of the
arrow molded into the valve. The bi-flow liquid line
solenoid valve is shipped as a single flow valve. The
carton contains another valve stem which needs
to be installed in the valve to convert it to a bi-flow
valve.
The bi-flow valve should be connected to the 24V
side of the contactor. When installing the valve, the
arrow should be positioned toward the compressor
section to minimize the transfer of liquid directly into
the coax in the heating mode. The solenoid should
be installed right after the filter-drier or within two
feet of the compressor section.