Carrier 33CS Installation, Service, And Troubleshooting Instructions

Also see for 33CS: Owner's manual Owner's manual Operating guide Installation, start-up, and operating instructions Installation, start-up, and operating instructions

Carrier 33CS Installation, Service, And Troubleshooting Instructions Manual pdf 31 page image

31To return the blinking display to normal:1. The display will return to normal when the supply airtemperature returns to within the limits of the current sys-tem operating mode. Refer to the System Time Guardssection on page 17 for more information.2. If the TEMP system thermostat does not utilize a DX coilsensor, but the DX Coil Temperature Sensor option hasbeen configured to ON, the annunciator will blink. Re-configure the DX Coil Sensor option.3. Check the TEMP system thermostat supply-air tempera-ture sensor or DX coil temperature sensor to see if thesensor is wired incorrectly or defective.Equipment Operation Problems — The TEMP sys-tem thermostat is designed to energize constant volume heat-ing and cooling equipment to satisfy the system comfortrequirements.When the TEMP system thermostat fails to pick a systemmode, or fails to energize the heating or cooling equipmentwhen expected, the problem usually involves the configurableoptions of the TEMP system thermostat.If the TEMP system thermostat selects a system mode, butthe heating or cooling equipment fails to energize, the problemmay be with the relay pack.TEMP SYSTEM THERMOSTAT FAILS TO SELECT SYS-TEM MODE — When the TEMP system thermostat fails toselect a system mode, check the items that influence the TEMPsystem thermostat to select system mode.1. The zone must be 1.5° F or more from set point.2. The TEMPsystem thermostat system switches (FAN,COOL, HEAT) must be set to AUTO or ON to operate.3. Ensure that the TEMP system thermostat Heating andCooling Time Guard has had time to expire. If the TimeGuard Between Modes option (category 4, option 2) hasbeen configured ON, the system will not operate untiltime guard has expired. Time guard delay occurs afterpower up, reset, or system mode has been released.Length of the time guard is (2.6 seconds x TEMP systemthermostat device address) + 5 minutes.If the Time Guard Between Modes option is configuredOFF, the length of the time guard is approximately1.5 minutes.The Time Guard Override option may be used to overridethe time guard to 30 seconds for one cycle. To activate theoverride, toggle category 4, option 3, ON and then OFF.4. Check the configuration of the TEMP system thermostatSystem Heating Mode Lockout, Heating Lockout Tem-perature Set Point, and Cooling Lockout Temperature SetPoint options. Based on the outside-air temperature, theTEMP system thermostat can lock out either system cool-ing or heating modes.TEMP SYSTEM THERMOSTAT FAILS TO ENERGIZESECOND STAGE — When the TEMP system thermostat failsto energize the second stage of the heating or cooling equip-ment, check the items that affect the decision of the TEMPsystem thermostat to energize the second stage of heating orcooling.1. When a system mode is selected and the reference zonedemand is equal to or greater than 8° F, the TEMP systemthermostat Energy Saver Lockout function automaticallydisables the second stage operation of the unit for approx-imately 20 minutes. This function saves energy by allow-ing the first stage of the heating or cooling unit to satisfythe system load at times of low thermal load (morningcool down or warm up).2. When the TEMP system thermostat Comfort Trend Stag-ing function (category 7, options 4 and 5) is configured toa value other than zero, the TEMP system thermostat willenergize the second stage of heating or cooling only afterit determines that the reference zone demand is not beingmet by the first stage of heating or cooling.If the Comfort Trend Staging function is configured off,the TEMP system thermostat will energize the secondstage 3 minutes after the first stage, if the demand of thereference zone is equal to or greater than 2° F.3. Check the TEMP system thermostat display for a flash-ing HEAT or COOL annunciator. A blinking annunciatorindicates a supply-air temperature problem.ANNUNCIATOR DISPLAYED BUT EQUIPMENT NOTENERGIZED — The TEMP system thermostat HEAT orCOOL annunciator is ON, but the heating or cooling equip-ment is not energized.Check the TEMP system thermostat Auxiliary Relay option(category 4, option 9). If the TEMP system thermostat is con-figured to operate an economizer, the TEMP system thermostatwill enable the economizer for first stage cooling when the out-side-air temperature is less than 64.9 F.Check the LEDs on the relay pack controlled by the TEMPsystem thermostat. Perform the correct procedure.LED Not Lit — The TEMP system thermostat HEAT orCOOL annunciator is ON but the LED on the relay pack is notlit. With the relay pack plugged in, check the voltages acrossthe relay pack input connector plug. Voltages should read ap-proximately 4 to 6 vdc (steady) between the black wire and theappropriate relay pack input wire. If not, replace relay pack.LED Is Lit — The TEMP system thermostat HEAT annuncia-tor is ON, the LED on the relay pack is lit, but the correspond-ing equipment stage is not energized.1. Check the AC voltage across the relay board common(red) and any deenergized relay (H1 or C1). The voltageshould read 24 vac. If not, check for wiring error.2. Check the AC voltage across the relay board common(red) and any indicated energized relay board output(FAN). The voltage should read near zero (<1 vac). If 24vac is read, check for bad relay board.3. Check the AC voltage across a suspected contactor coil.The voltage should read 24 vac. If not, check the contac-tor coil wiring.4. Other possibilities are: bad contactor, defective equip-ment, or no unit power.

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