Carrier WeatherMaker 48A2020 Controls, Start-up, Operation, Service And Troubleshooting Instructions

107This alarm will disable mechanical cooling and will require amanual reset. This alarm may be disabled once the reverse ro-tation check has been verified by setting Configuration COOLREV.R = Yes.A150 (Unit is in Emergency Stop)If the fire safety input condition occurs to indicate a fire orsmoke condition, then Alarm code 150 will occur and the unitwill be immediately stopped. Through separate inputs the unitcan be put into purge, evacuation, and pressurization. This re-quires a manual reset.If the CCN point name “EMSTOP” in the System table is set toemergency stop, the unit will shut down immediately andbroadcast an alarm back to the CCN indicating that the unit isdown. This alarm will clear when the variable is set back to“enable.”A151 (Illegal Configuration - More Than Two Elec. HeatStages)The unit cannot be configured with more than two electric heatstages. An alarm code will occur when the unit is wronglyconfigured.T153 (Real Time Clock Hardware Failure)A problem has been detected with the real timeclock on theMBB. Try resetting the power and check the indicator lights. Ifthe alert continues, the board should be replaced.A154 (Serial EEPROM Hardware Failure)A problem has been detected with the EEPROM on the MBB.Try resetting the power and check the indicator lights. If thealarm continues, the board should be replaced.T155 (Serial EEPROM Storage Failure Error)A problem has been detected with the EEPROM storage on theMBB. Try resetting the power and check the indicator lights. Ifthe alert continues, the board should be replaced.A156 (Critical Serial EEPROM Storage Failure Error)A problem has been detected with the EEPROM storage on theMBB. Try resetting the power and check the indicator lights. Ifthe alarm continues, the board should be replaced.A157 (A/D Hardware Failure)A problem has been detected with A/D conversion on theboards. Try resetting the power and check the indicator lights.If the alarm continues, the board should be replaced.A168 (Low Ambient Control Board (SCB2) Comm Failure)This alarm indicates that there are communications problemswith the Low Ambient Option SCB2 board. Cooling on theunit is disabled until communication with the SCB2 controlboard is re-established. The alarm will automatically reset.Reason for failure may be due to incorrect wiring, power lossto the control board, or damage to the RS-485 drivers on theLEN bus.A169 (Expansion Valve Control Board Comm Failure)Cooling is disabled until communication with the EXV controlboard is re-established. Recovery is automatic. Reason for fail-ure may be due to incorrect wiring, power loss to the control.A171 (Staged Gas Control Board Comm Failure)This alarm indicates that there are communications problemswith the staged gas heat control board, which is located in thegas section on units equipped with staged gas heat. If thisalarm occurs, the staged gas heat will be disabled. The alarmwill automatically reset.A172 (Controls Expansion Module Comm Failure)This alarm indicates that there are communications problemswith the controls expansion board. All functions performed bythe CEM will stop, which can include demand limit, reset, firecontrol modes, and the fan status switch. The alarm will auto-matically reset.A173 (ECB1 Board Communication Failure)This alarm indicates that there are communications problems withthe economizer control board. This will result in the economizerand the power exhaust not working and the dampers to be fullyclosed. The exhaust fans will stop. The alarm will automaticallyreset.A174 (ECB2 Board Communication Failure)This alarm indicates that there are communications problemswith the ECB2 which controls the VAV unit indoor fan inverterspeed and hot gas bypass on CV and VAV units. Because thecontrol of the fan is critical to unit operation, the unit will bestopped. The alarm will automatically reset.T177 (4-20 mA Demand Limit Failure)This alert indicates a problem with the optional remote 4 to 20 mAdemand limit signal (Inputs4-20DLM.M) that is connectedto the CEM module (if the signal reads less than 2 mA). If this oc-curs, then demand limiting will be disabled. The unit must be con-figured for 4 to 20 mA Demand Limiting using the Demand LimitSelect (ConfigurationDMD.LDM.L.S).T178 (4-20 mA Static Pressure Reset/VFD Failure)If this transducer fails (if the signal reads less than 2 mA on theinput of the CEM module), and the unit is configured to per-form static pressure reset or remote control of the supply fanVFD with this transducer, no static pressure reset or VFD con-trol will be performed and an alert will be generated. Recoveryis automatic. Reason for error is either a faulty sensor, wiringerror, or damaged input on the CEM control board.A179 Circuit A ODF VFD FailureThe MBB has received a fault status from the outdoor fanVFD(s). The A circuit of the 60 ton MCHX or the unit will notbe allowed to operate, and a manual reset is required. The VFDkeypad will indicate which fault has occurred.A180 Circuit B ODF VFD FailureThe MBB has received a fault status from the outdoor fanVFD(s). The B circuit of the 60 ton MCHX or the unit will notbe allowed to operate, and a manual reset is required. The VFDkeypad will indicate which fault has occurred.A181 Circuit A ODF VFD Communication FailureThis alarm indicates that there are communication problemswith the Circuit B OD fan VFD. The cooling function on the Bcircuit or the unit is disabled until communication with the ODfan VFD(s) is re-established.A182 Circuit B ODF VFD Communication FailureThis alarm indicates that there are communication problemswith the Circuit B OD fan VFD. The cooling function on the Bcircuit or the unit is disabled until communication with the ODfan VFD(s) is re-established.T183 (Compressor Lockout Low Ambient)When the outdoor ambient temperature (OAT) is below the com-pressor lockout temperature setting (OATLCOMP), an alert willoccur to indicate the setting situation. If the unit is equipped withLow Ambient or GreenSpeed option, the OATLCOMP setting canbe lower than the default 40°F to the minimum of –20°F.A200 (Linkage Timeout Error — Comm Failure)If linkage is established via the CCN with ComfortID™ termi-nals, a 5-minute timeout on loss of communication will bemonitored. If 5 minutes expires since the last communicationfrom a VAV Linkage Master, the unit will remove the link andflag the alert. When the rooftop loses its link, the temperatureand setpoints are derived locally. Recovery is automatic on re-establishment of communications. Reason for failure may bewiring error, too much bus activity, or damaged 485 drivers.