Carrier 38MGQ Series Service Manual

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Carrier 38MGQ Series Service Manual Manual pdf 30 page image

30REFRIGERANT LINESGeneral refrigerant line sizing:1 The outdoor units are shipped with a full charge of R410Arefrigerant. All charges, line sizing, and capacities are based onruns of 25 ft (7.6 m) per number of zones. For runs over 25 ft(7.6 m), consult long--line section on this page for propercharge adjustments.2 Minimum refrigerant line length between the indoor andoutdoor units is 10 ft. (3 m).3 Refrigerant lines should not be buried in the ground. If it isnecessary to bury the lines, not more than 36--in (914 mm)should be buried. Provide a minimum 6--in (152 mm) verticalrise to the service valves to prevent refrigerant migration.4 Both lines must be insulated. Use a minimum of 1/2--in.(12.7 mm) thick insulation. Closed--cell insulation isrecommended in all long--line applications.5 Special consideration should be given to isolatinginterconnecting tubing from the building structure. Isolatethe tubing so that vibration or noise is not transmitted intothe structure.IMPORTANT: Both refrigerant lines must be insulated separately.S The following maximum lengths are allowed:Table 16—Refrigerant LinesSystem size 18K 27K 36K 48KPipingMin. Piping Length ft (m) 10 (3) 10 (3) 10 (3) 10 (3)Standard Piping Length ft (m) 25 (7.5) 25 (7.5) 25 (7.5) 25 (7.5)Max. outdoor--indoor height difference ft (m) 32(10) 32(10) 32(10) 32(10)(OU higher than IU)Max. outdoor--indoor height difference ft (m) 49(15) 49(15) 49(15) 49(15)(IU higher than OU)Max. Piping Length with no additional refrigerantcharge per zone. ft (m) 24.6(7.5) 24.6(7.5) 24.6(7.5) 24.6(7.5)Max. Length for one indoor unit ft (m) 65.6(20) 82(25) 98(30) 98(30)Max. height different between indoor units ft (m) 32(10) 32(10) 32(10) 32(10)Total Maximum Piping Length Ft. (m) 98(2*15=30) 147(3*15=45) 196(4*15=60) 245(5*15=75)Additional refrigerant charge Oz/ft (g/m) 0.16(15) 0.16(15) 0.16(15) 0.16(15)(between Standard – Max piping length)Gas Pipe in 3/8*2 3/8*3 1/2+3/8*3 1/2+3/8*3Liquid Pipe in 1/4*2 1/4*3 1/4*4 1/4*5Refrigerant Refrigerant Type R410A R410A R410A R410AHeat Pump Models Charge Amount Lbs (kg) 4.19 (1.9) 6.17 (2.8) 7.94 (3.6) 10.14 (4.6)NOTE: The refrigerant charge included is adequate for the numberof zones multiplied by the max. piping length with no additionalrefrigerant.Long Line Applications,:1 No change in line sizing is required.2 Add refrigerant per Table 17.Table 17—Additional Charge Table Per ZoneUnitSizeTotal Line Lengthftper indoor unitAdditional Charge, oz/ft.ft (m)Min Max 10 -- 25(3 -- 8)>25 -- 66(8 -- 20)>66 -- 82(20 -- 25)>82 -- 98(25 -- 30)181066None 0.1627 820.1636 98 0.1648