Carrier Weathermaster 38HQ Installation, Start-up And Service Instructions Manual

defrost thermostat contacts will open to terminatedefrosting before 10 minutes have elapsed. Thedefrost thermostat contacts open at 80 (± 6) F liquidrefrigerant temperature. When defrosting is ter¬minated, the outdoor fan motor is energized and thereversing valve solenoid is de-energized returningunit to heating cycle.If the defrost thermostat contacts are open, (noneed for defrost cycle), system operates for another90-minute interval before attempting anotherdefrost cycle.SERVICEHeat Pump Circuits shown in Fig. 9 are refrigerantflow diagrams for heating and cooling cycles.Refrigerant Charging — Each indoor compressorsection is shipped with a vapor holding charge; out¬door coil section contains partial system chargeas shown in Table 7. Add refrigerant to system sothat total required charge is attained as describedbelow. Refer to Carrier Standard Service TechniquesManual, Chapter 1, Refrigerants for additionalinformation.Adjust system charge for refrigerant line lengthsand diameters that differ from 25 ft and 3/ 8-in. O.D.(liquid line), respectively, using refrigerant weightsTable 7 — Service DataSYSTEMIndoor Compr Section 38HQ227 38HQ234Outdoor Coil Section 38HQ940 38HQ960Fan Propeller, Direct DriveCfm 3100 3600Rpm 1015 1080Diam (in.) 20 20Motor Hp 1/5 1/4Factory Charge (lbs, R-22) 7 1 100Total Req'd Charge (lbs, R-22) 92 11 0Additional Charge Req'd (lbs) 2 1 1 0shown in table below. (Twenty-five feet of 3/8-in.O.D. tubing contains 14.4 oz of R-22.) Add R-22charge to system if liquid line is over 25 ft; removecharge if liquid line is shorter than 25 feet.LIQUID LINE OUNCES OF R-22/FT LENGTHDIAM (in.) OF LIQUID LINE3/8 585/16 361/4 1 21When recharging is necessary during heating orcooling season, weigh in total charge indicated inTable 7. (Charge must be weighed in during heatingseason.) Remove any refrigerant remaining in sys¬tem before recharging. If system has lost complete(COOLING CYCLE)BYPASSACCURATERBYPASSACCURATERSTRAINERSERVICE VALVES(HEATING CYCLE)BYPASS -ACCURATERSTRAINERSERVICE VALVESFig. 9 — Refrigerant Flow Diagrams