Reznor MASA Unit Installation Manual - Manual (Page 11)

Form I-COND, P/N 220746R6, Page 11
6.1.3 Refrigerant Piping Guidelines (R-410A Refrigerant)
The information in this section is a guideline and is not intended to provide
all of the instructions needed for designing and installing the R-410A refriger-
ant lines. The installer is responsible for designing the refrigerant connecting
system and for complying with standard refrigerant piping procedures. Refer
to ASHRAE Guide and ASME Informational Standards for piping information.
Comply with CSA Mechanical Refrigeration Code CSA B52, ASHRAE Guide
Section 15, all municipal codes, and state or provincial requirements.
Read all information in Section 6.1.3 before beginning installation of refrigerant
piping. In addition to the information in the following paragraphs, these general
requirements apply.
•
IMPORTANT: Do not bury refrigeration lines.
•
Pitch refrigerant lines in the direction of flow at approximately 1/2” per 10 ft
(12mm per 3 M).
•
To prevent possible noise or line vibration, isolate refrigerant lines from
building structure and ductwork.
•
Use long radius “L” for all 90° bends.
•
Isolate suction and liquid lines from each other and from the unit cabinet.
CAUTION
Do not leave system open to the atmosphere any longer
than minimum time required for installation. POE oil in the
compressors is extremely susceptible to moisture absorption.
Keep ends of tubing sealed during installation. See Hazard
Levels, page 3.
6.1.3.1 Type of Refrigerant Piping
Refrigerant piping is field supplied. Use only clean, dehydrated refrigeration
grade Type L scheduled or ACR Hard Drawn (ASTM B 280) copper tubing.
Size of refrigerant line segments depends on the condensing unit size and the
length and configuration of the lines. Do not determine the size of the piping
by the size of the connections at the condenser or evaporator; follow the line
sizing instructions in Section 6.1.3.2 below.
6.1.3.2 Refrigerant Piping Length and Size
Design the refrigerant circuit for a minimum pressure loss by keeping the actual
length to a minimum, with a minimum number of bends and fittings, and with
a minimum amount of line exposed to the outdoors. Excessive suction line
pressure drop will result in decreased thermal efficiency and increased power
requirements. Excessive liquid line pressure drop can cause the refrigerant to
flash resulting in faulty expansion valve operation. Typically, each segment of
the refrigerant line should be sized for pressure loss of 2°F or less.
Lift must also be considered when determining location and piping length.
Maximum lift of the refrigerant circuit is 45 ft (13.7M).
Tubing size is determined separately for each of the four segments of the
refrigerant piping - Circuit A liquid line; Circuit A suction line; Circuit B liquid line;
and Circuit B suction line. The size of the tubing required for each segment is
determined by its equivalent length. The equivalent length is the actual length
of the line segment plus any fittings or accessories.
If accessories (see Paragraphs 6.1.3.3 and.4 for required accessories) have
equivalent lengths provided by the manufacturer, use that information. If
equivalent length is not provided and for fittings, use the equivalent lengths in
TABLE 2.