Carrier 50HX Installation, Start-up, And Operating Instructions Manual

Also see for 50HX Guide: Manual

START UP AND MAKE ADJUSTMENTSComplete the required procedures given in the Pre-Start- Upsection before starting the unit. Do not jumper any safetydevices when operating the unit. Do not operate the compres-sor when the outdoor temperature is below 40°F (unlessaccessory low-ambient kit is installed). Do not rapid-cycle thecompressor. Allow 5 minutes between “on” cycles to preventcompressor damage.CHECKING COOLING CONTROL OPERATIONStart and check the unit for proper cooling control operation asfollows:1. Place room thermostat SYSTEM switch in OFF position.Observe that blower motor starts when FAN switch is placedin ON position and shuts down when FAN switch is placed inAUTO position.2. Place SYSTEM switch in COOL position and FAN switch inAUTO position. Set cooling control below room temperature.Observe that compressor, outdoor fan, and indoor blowermotors start. Observe that compressor and outdoor fan shutdown when control setting is satisfied and that indoor blowershuts down after fan time delay expires.3. When using an auto-changeover room thermostat, place bothSYSTEM and FAN switches in AUTO positions. Observe thatunit operates in heating mode when temperature control is setto “call for heating” (above room temperature) and operates incooling mode when temperature control is set to “call forcooling” (below room temperature).CHECKING HEATING CONTROL OPERATIONStart and check the unit for proper cooling control operation asfollows:1. Place room thermostat SYSTEM switch in OFF position.Observe that blower motor starts when FAN switch is placedin ON position and shuts down when FAN switch is placed inAUTO position.2. Place SYSTEM switch in HEAT position and FAN switch inAUTO position. Set cooling control above room temperature.Observe that compressor, outdoor fan, and indoor blowermotors start. Observe that compressor and outdoor fan shutdown when control setting is satisfied and that indoor blowershuts down after fan time delay expires.3. When using an auto-changeover room thermostat, place bothSYSTEM and FAN switches in AUTO positions. Observe thatunit operates in heating mode when temperature control is setto “call for heating” (above room temperature).4. If system is equipped with supplemental or emergency heat(resistance heaters), observe that when thermostat is placed inEMERGENCY HEAT mode and temperature control is setabove room temperature that heaters and indoor blower comeon. Observe that heaters shut off when control setting issatisfied and that the indoor blower shuts off after fan timedelay expires.CHECKING AND ADJUSTING REFRIGERANT CHARGEThe refrigerant system is fully charged with R-22 refrigerant,tested, and factory-sealed.NOTE: Adjustment of the refrigerant charge is not requiredunless the unit is suspected of not having the proper R-22 charge.A superheat charging chart is attached to the outside of thecompressor access panel. The chart includes the required suctionline temperature at given suction line pressures and outdoorambient temperatures (See Table 13A-H and Fig. 30).An accurate superheat, thermocouple- or thermistor-type ther-mometer, a sling psychrometer, and a gauge manifold are requiredwhen using the superheat charging method for evaluating the unitcharge. Do not use mercury or small dial-type thermometersbecause they are not adequate for this type of measurement.NOTE: Allow system to operate in the cooling mode for aminimum of 10 minutes before checking or adjusting refrigerantcharge.When evaluating the refrigerant charge, an indicated adjust-ment to the specified factory charge must always be veryminimal. If a substantial adjustment is indicated, an abnormalcondition exists somewhere in the cooling system, such asinsufficient airflow across either coil or both coils. Failure toadjust charge properly or correct the abnormal conditions willcause damage to the unit.Proceed as follows:1. Remove caps from low- and high-pressure service fittings.2. Using hoses with valve core depressors, attach low- andhigh-pressure gauge hoses to low- and high-pressure servicefittings, respectively.3. Start unit in Cooling mode and let unit run until systempressures stabilize.4. Measure and record the following:a. Outdoor ambient-air temperature (°F db).b. Indoor coil inlet-air temperature (°F wb).c. Suction-tube temperature (°F) at low-side service fitting.d. Suction (low-side) pressure (psig).5. Using “Superheat Charging Charts” compare outdoor-air tem-perature (°F db) with the Indoor coil air inlet temperature (°Fwb) to determine desired system operating superheat tempera-ture. See Table 13A–H and Fig. 30.6. Using ’’Required Suction-Tube Temperature (F)’’ table, com-pare desired superheat temperature with suction (low-side)operating pressure (psig) to determine proper suction-tubetemperature. See Fig. 30.Fig. 25—Fan Blade ClearanceC950271/2 IN. MAXFROM FAN DECKMOTOR SHAFTMOTOR20