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Figure 12. Indoor coil with two distributors (single-circuit TTA/TWA units)
Notes:
1. Pitch the liquid line 1 inch per 10 feet (1 cm per 3 m) so that the liquid refrigerant drains toward the indoor coil. Use
the liquid-line size recommended in Table 2, p. 25, or Table 3, p. 26.
2. Provide one expansion valve (TXV) per distributor.
TWA heat pumps only: Provide one check valve for each expansion valve.
3. Pitch the gas line leaving the coil so that it slopes away from the coil by 1 inch per 10 feet (1 cm per 3 m).
4. Use the DETINT to prevent oil and refrigerant migration when the unit is off. The DETINT also serves to isolate the
TXV bulb from suction-header conditions. See “Line Sizing, Routing, and Component Selection,” p. 9.
5. For all coil branch circuits in the gas line, use a tube diameter that is one size smaller than the gas-line size
recommended in Table 2, p. 25 or Table 3, p. 26.
6. For vertical risers, use the tube diameter recommended in Table 2, p. 25 or Table 3, p. 26. Ensure that the top of the
riser is at least 1 foot (30 cm) above the lowest point.
7. Pitch the gas line by 1 inch per 10 feet (1 cm per 3 m) toward the indoor coil.
8. Insulate the gas line.
Refrigerant Piping Examples
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