Carrier 52S Series Service Technician Manual

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Carrier 52S Series Service Technician Manual Manual pdf 26 page image

SEQUENCE OF OPERATIONn HEAT/COOL UNITS(Figure 50)Fan Mode — With the selector switch set to FAN andthe fan switch set to fan cycle, contacts L1 to LO andFCS1 to LS are made.Cooling (Low) — With the selector switch set to lowspeed cooling and the fan switch set to fan cycle, contactsFCS2 to LO, COMP to FCS1, and COMP to IT3 aremade.NOTE: The contact in low cooling sequence of operationfor FCS2 is MED on units built prior to 1996.Cooling (High) — With the selector switch set to highspeed cool and the fan switch set to fan cycle, contactsFCS2 to HI, COMP to FCS1, and COMP to IT3 are made.Heating (Low) — With the selector switch set to lowspeed heat and the fan switch set to fan cycle, contactsFCS2 to LO, IT1 to LS, L2 to HTR, and FCS1 to LSare made.NOTE: The contact in low heating sequence of operationfor FCS2 is MED on units built prior to 1996.Heating (High) — With the selector switch set to highspeed heat and the fan switch set to fan cycle, con-tacts FCS2 to HI, IT1 to LS, L2 to HTR, and FCS1 toLS are made.n COOLING ONLY UNITS (Figure 51)Fan Mode — With the selector switch set to FAN andthe fan switch set to fan cycle, contact L1 to LO is made.Cooling (Low) — With the selector switch set to lowspeed cooling and the fan switch set to fan cycle, contactsFCS to LO and L1 to IT3 are made.NOTE: The contact in low cooling sequence of operationfor FCS2 is MED on units built prior to 1996.Cooling (High) — With the selector switch set to highspeed cool and the fan switch set to fan cycle, contactsFCS to HI, L1 to IT3 are made.n HEAT PUMP UNITS (Figure 52)Fan Mode — With the selector switch set to fan cycle,contacts L1 to LO are made.Cooling (Low) — With the selector switch set to lowcool and the fan switch set to fan cycle, contacts L1 toIT3 and FCS to LO are made.NOTE: The contact in low cooling sequence of operationfor FCS2 is MED on units built prior to 1996.Cooling (High) — With the selector switch set to highcool and the fan switch set to fan cycle, contacts L1 toIT3 and FCS to HI are made.Heating (Low) — With the selector switch set to lowheat and the fan switch set to fan cycle, contacts L1 toIT1, FCS to LO and L2 to HTR are made.Heating (High) — With the selector switch set to highheat and the fan switch set to fan cycle, contacts L1 toIT1, FCS to HI, and L2 to HTR are made.Defrost Cycle — When heat pump unit is operating inreverse cycle, the outdoor coil may begin to frost. As frostaccumulates on the outdoor coil the unit may switchinto defrost mode. The defrost mode is activated whenthe outdoor frost thermostat sensor detects a tem-perature below 15 F on the coil. At this point, the ther-mostat deenergizes the compressor and activates theelectric heat. The unit will remain in electric heat modeuntil the outdoor thermostat senses 35 F. The defrostmode is a passive operation and may take some time be-fore the coil defrosts.SWITCHPOSITION CONTACTS MADEOFF FCS TO LSFAN L1 TO LO*, FCS1 TO LSLO HEAT FCS2 TO LO, IT1 TO LS, L2 TO HTR, FCS1 TO LSHI HEAT FCS2 TO HI, IT1 TO LS, L2 TO HTR, FCS1 TO LSLO COOL FCS2 TO LO, COMP TO FCS1, COMP TO IT3HI COOL FCS2 TO HI, COMP TO FCS1, COMP TO IT3*L1 to MED, some models.FIGURE 50 — SELECTOR SWITCH CONTACTS,ALL 52SE AA AND CP MODELSSWITCHPOSITION CONTACTS MADEOFF NONEFAN L1 TO LO*LO COOL L1 TO IT3, FCS TO LOHI COOL L1 TO IT3, FCS TO HI*L1 to MED, some models.FIGURE 51 — SELECTOR SWITCH CONTACTS,ALL 52SC AA AND CP MODELSSWITCHPOSITION CONTACTS MADEOFF NONEFAN L1 TO LO*LO HEAT L1 TO IT1, FCS TO LO, L2 TO HTRHI HEAT L1 TO IT1, FCS TO HI, L2 TO HTRLO COOL L1 TO IT3, FCS TO LOHI COOL L1 TO IT3, FCS TO HI*L1 to MED, some models.FIGURE 52 — SELECTOR SWITCH CONTACTS,ALL 52SQ AA AND CP MODELS52SSERIES26