LC097HV4 User Manual

Loading ...

REFRIGERANT PIPING DESIGN

Definitions

Physical Pipe Length: Actual length of straight segment(s) of pipe.

Equivalent Pipe Length: Actual length of pipe plus equivalent lengths of long radius elbows, Y-branches, and valves.

1. Draft a one-line diagram of the proposed piping system connecting outdoor unit to indoor units. Follow the pipe limitations listed on page

64.

2. Calculate the physical length of each pipe segment and note it on the drawing.

3. Calculate the equivalent pipe length of each pipe segment.

Using Elbows

Field-supplied elbows are allowed as long as they are long radius and designed

for use with R410A refrigerant. The designer should be cautious with the quantity

and size of fittings used, and must account for the additional pressure losses in

equivalent pipe length calculation. The equivalent pipe length of each elbow must

be added to each pipe segment. See Table 40 for equivalent lengths.

Table 40: Equivalent Piping Length for Piping Components.

Layout Procedure

Component

Size (Inches)

1/4 3/8 1/2 5/8 3/4

Long Radius Elbow (ft.)

0.5 0.6 0.7 0.8 1.2

Field-Provided Isolation Ball Valves

It is acceptable to install field-supplied ball valves with Schrader ports at the indoor unit. Full-port isolation ball valves with Schrader ports

(positioned between valve and indoor unit) rated for use with R410A refrigerant should be used on both the liquid and vapor lines.

If valves are not installed and the indoor unit needs to be removed or repaired, the entire system must be shut down and evacuated. Position

valves with a minimum distance of three (3) to six (6) inches of pipe on either side of the valve. Valves must be easily accessible for service.

If necessary, install drywall access doors or removable ceiling panels, and position the valves to face the access door or ceiling panel open-

ing. Mount valves with adequate space between them to allow for placement of adequate pipe insulation around the valves. Recommended

best practice is to clearly label and document locations of all service valves. The equivalent pipe length of each ball valve must be added to

each pipe segment.

Figure 48: Installing Piping Above and Below an Obstacle.

Above an obstacle.

Minimum

Below an obstacle.

Obstacles

When an obstacle, such as an I-beam or concrete T, is in the path

of the planned refrigerant pipe run, it is best practice to route the

pipe over the obstacle. If adequate space is not available to route

the insulated pipe over the obstacle, then route the pipe under the

obstacle. In either case, it is imperative the horizontal section of pipe

above or below the obstacle be a minimum of three (3) times greater

than the longest vertical rise (or fall) distance.

Selecting Field-Supplied Copper Tubing / Refrigerant Piping System Layout

In-line Refrigeration Components

Components such as oil traps, solenoid valves, filter-dryers, sight glasses, tee fittings, and other after-market accessories are not permitted

on the refrigerant piping system between the outdoor unit and the indoor unit. Single Zone air-source systems are provided with redundant

systems that assure oil is properly returned to the compressor. Sight-glasses and solenoid valves may cause vapor to form in the liquid

stream. Over time, dryers may deteriorate and introduce debris into the system. The designer and installer verify the refrigerant piping sys-

tem is free of traps, sagging pipes, sight glasses, filter dryers, etc.

Due to our policy of continuous product innovation, some specications may change without notication.

66 | FOUR-WAY CASSETTE

Four-Way Ceiling Cassette System Engineering Manual

Loading ...

User Manual - Page 66