Carrier 50ZH024-060 Installation, Start-up And Service Instructions Manual

Also see for 50ZH024: Product data Installation instructions

Contents

Step 1—Check for Refrigerant LeaksLOCATE AND REPAIR REFRIGERANT LEAKS ANDCHARGE THE UNIT AS FOLLOWS:1. Using both high- and low-pressure ports, locate leaks andreclaim remaining refrigerant to relieve system pressure.2. Repair leak following accepted practices.NOTE: Install a liquid-line filter drier whenever the system hasbeen opened for repair.Step 2—Start-Up Cooling Section and Make AdjustmentsComplete the required procedures given in the Pre-Start- Upsection this page before starting the unit. Do not jumper anysafety devices when operating the unit.Do not operate the compressor when the outdoor temperatureis below 40 F.Do not rapid-cycle the compressor. Allow 5 minutes between‘‘on’’ cycles to prevent compressor 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 within 30 seeconds when FANswitch is placed in AUTO 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 and that reversing valve shifts. Observe thatcooling cycle shuts down when control setting is satisfied.Reversing valve (RV) remains energized.3. Place system switch in HEAT position. Observe that compres-sor, indoor fan and outdoor fan energize (Reversing Valve isdeenergized in heat pump heating mode). Set control aboveroom temperature. Observe that heating cycle shuts downwhen control setting is satisfied.4. When using an automatic changeover room thermostat, placeboth SYSTEM and FAN switches in AUTO. positions.Observe that unit operates in Cooling mode when temperaturecontrol is set to ‘‘call for cooling’’ (below room temperature),and unit operates in Heating mode when temperature controlis set to “call for heating” (above room temperature).COMPRESSOR ROTATIONOn 3–Phase units it is important to be certain compressor isrotating in the proper direction. To determine whether or notcompressor is rotating in the proper direction:1. Connect service gages to suction and discharge pressurefittings.2. Energize the compressor.3. The suction pressure should drop and the discharge pressureshould rise, as is normal on any start-up.If the suction pressure does not drop and the discharge pressuredoes not rise to normal levels:1. Turn off power to the unit and tag disconnect.2. Reverse any two of the unit power leads.3. Turn on power to the unit.The suction and discharge pressure levels should now move totheir normal start-up levels.NOTE: When the compressor is rotation in the wrong direction,the unit makes an elevated level of noise and does not providecooling.Step 3—Refrigerant ChargeRefrigerant Charge — Amount of refrigerant charge is listed onunit nameplate and in Table 1. Refer to Carrier Refrigerant ServiceTechniques Manual, Refrigerants section. Unit panels must be inplace when unit is operating during charging procedure. Unit mustoperate a minimum of 15 minutes before checking charge.NO CHARGERefer to Carrier Refrigerant Service Techniques. Use standardevacuating techniques. After evacuating system, weigh in thespecified amount of refrigerant (refer to Table 1).LOW CHARGE COOLINGUsing cooling charging chart (see Fig. 16–21),Vary refrigerantuntil conditions of the chart are met. Note that charging chart isdifferent from those normally used. Charts are based on chargingthe units to the correct superheat for the various operatingconditions. An accurate pressure gage and temperature-sensingdevice is required. Connect the pressure gauge to the service porton the suction line. Connect temperature sensing device to thesuction line near the compressor and insulate it so that outdoorambient temperature does not affect reading.TO USE THE COOLING CHARGING CHARTThis method is to be used in cooling mode only. Take the outdoorambient temperature and read the suction pressure gauge. Refer to3-PHASECONNECTIONSTO DISCONNECTPER NECSINGLE-PHASECONNECTIONSTO DISCONNECTPER NECGROUNDLEADUNIT GROUNDBLKYELBLULLLC00012Fig. 13—Line Power ConnectionsYCW2EGROTHERMOSTATAND SUBBASEUNIT CONTROL POWERSPLICE BOXBRNWHTYELGRNREDORNC99056Fig. 14—Control Connections10