Carrier 24AHA4 Service Manual

Contents

Carrier 24AHA4 Service Manual Manual pdf 14 page image

14REFRIGERANT LINESGeneral refrigerant line sizing:1 The outdoor units are shipped with a full charge of R410Arefrigerant. All charges, line sizing, and capacities are basedon runs of 25 ft (7.6 m). For runs over 25 ft (7.6 m), refer tothe Residential Long Line Guide.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. Isolate thetubing so that vibration or noise does not transmit into thestructure.IMPORTANT: Both refrigerant lines must be insulatedseparately.S The following maximum lengths are allowed:Table 12 – Maximum Refrigerant Line LengthsUnitSizeMax LineLength* ft(m)Max Elevation(ID over OD) ft( m)Max Elevation(OD over ID) ft (m)18K 250 (76.2) 65 (19.8) 200 (61)24K 250 (76.2) 65 (19.8) 200 (61)30K 250 (76.2) 65 (19.8) 200 (61)36K 250 (76.2) 65 (19.8) 200 (61)Note: For lengths greater than 25 ft. (7.6 m), refer to the ResidentialLong Line Guide.*Maximum actual length not to exceed 200 ft. (61 m). Total equivalentlength accounts for losses due to elbows or fitting. See the Long LineGuideline for details.S The following are the piping sizes.Table 13 – Pipe SizesPipe Sizes (in)Unit Size Mix Phase -- in Vapor -- in18K 3/8 5/824K 3/8 3/430K 3/8 3/436K 3/8 7/8Note: Both lines need to be insulated using at least 1/2 inch closedfoam insulation.Refrigerant ChargeTable 14 – Charge RequirementsSystemTypeNominalCapacity Outdoor Unit Indoor UnitCharge toSub--cooling Deltafrom Rating PlateValueCoolingOnly018 24AHA418A003 124ANS018000 40MKCB18B----3 12022 24AHA424A003 124ANS024000 40MKCB22B----3 12028 24AHA430A003 124ANS030000 40MKCB28B----3 12032 24AHA436A003/5/6 124ANS036000 40MKCB32B----3 8HeatPump024 25HHA424A003 224ANS024000 40MKQB24B----3 14028 25HHA430A003 224ANS030000 40MKQB28B----3 11The above additional charge is required amount for line lengths up to25 ft (7.6 m). For line lengths exceeding 25 ft. (7.6 m), additionalcharge will be required. Refer to the Residential Long Line Guide.Metering DeviceThe metering device(s) for these systems is a type B accurator. Thecooling accurator is installed with the indoor unit, while theheating accurator is installed with the outdoor unit. One Accuratoris required for the cooling only system and two are required for theheat pump systems. Refer to Table 15 for the accurator size.Table 15 – Accurator SizesSystem Size Cooling Only Heat Pumps40MKC**B 40MKQ**B 25HHA4/224ANS018 0.046” -- --022, 024 0.052” 0.052” 0.049”028 0.059” 0.057” 0.055”032 0.065” -- --SYSTEM EVACUATION ANDCHARGINGUNIT DAMAGE HAZARDFailure to follow this caution may result in equipmentdamage or improper operation.Never use the system compressor as a vacuum pump.CAUTION!Refrigerant tubes and indoor coil should be evacuated using therecommended deep vacuum method of 500 microns. The alternatetriple evacuation method may be used if the procedure outlinedbelow is followed. Always break a vacuum with dry nitrogen.SYSTEM VACUUM AND CHARGEUsing Vacuum Pump1 Completely tighten flare nuts A, B, C, D, connect manifoldgage charge hose to a charge port of the low side servicevalve (see Fig. 16).2 Connect charge hose to vacuum pump.3 Fully open the low side of manifold gage (see Fig. 17).4 Start the vacuum pump.5 Evacuate using either deep vacuum or triple evacuationmethod.6 After evacuation is complete, fully close the low side ofmanifold gage and stop operation of vacuum pump.7 The factory charge contained in the outdoor unit is good for upto 25 ft. (8 m) of line length. For refrigerant lines longer than25 ft. (8 m), add charge, up to the maximum allowable length,as specified in the residential Long Line Application Guide.8 Disconnect charge hose from charge connection of the lowside service valve.9 Fully open service valves B and A.10 Securely tighten caps of service valves.Outdoor Unit Indoor UnitRefrigerantService ValveLow SideHigh SideABCDA07360Fig. 16 – Service ValveManifold Gage500 micronsLow side valve High side valveCharge hose Charge hoseVacuum pumpLow side valveA07361Fig. 17 – Manifold