Carrier 58TUA Installation, Start-up, And Operating Instructions Manual

Also see for 58TUA: Service and maintenance instructions User's information manual User's information manual Installation, start-up, and operating instructions Installation, start-up, and operating instructions

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Carrier 58TUA Installation, Start-up, And Operating Instructions Manual Manual pdf 16 page image

(1.) Gas input for low- and high-fire operation.(2.) Derate for altitude if applicable.(3.) Return and supply ducts for excessive restrictionscausing static pressures greater than 0.50-in. wc.c. Adjust air temperature rise by adjusting blower speed.Increase blower speed to reduce temperature rise. Decreaseblower speed to increase temperature rise. For high fire,speed selection can be med-high or med-low (factorysetting). For low fire, speed selection can be low (factorysetting) or med-low if high-fire speed selection is med-high.Disconnect the electrical power before changing the speedtap. A failure to follow this warning can cause personalinjury.d. To change motor speed selection for high heat, removeblower motor lead from control HIGH-GAS-HEAT termi-nal (See Fig.10. and 12.). Select desired blower motorspeed lead from 1 of the other terminals and relocate it tothe HIGH-GAS-HEAT terminal. (See Table 10 for leadcolor identification.) Reconnect original lead to the PARKterminal. Follow this procedure for proper selection of cooland low-gas-heat speed selection.Recheck the temperature rise. It must be within the limitsspecified on the unit rating plate. Recommended operation isat midpoint of rise range or above.3. Set thermostat heat anticipator.a. When using a nonelectronic thermostat, the thermostat heatanticipation must be set to match the amp draw of theelectrical components in the R-W/W1 circuit. Accurateamp draw readings can be obtained at the wires normallyconnected to thermostat subbase terminals R and W/W1.Fig. 15 illustrates an easy method of obtaining the actualamp draw. The amp reading should be taken after theblower motor has started and the furnace is operating inlow fire. To operate the furnace in low fire, first moveSW-2 to ON position, THEN connect the ammeter wires asshown in Fig. 15. The thermostat anticipator should NOTbe in this circuit while measuring the current. If thethermostat has no subbase, the thermostat MUST bedisconnected from the R and W/W1 wires during thecurrent measurement. Return SW-2 to final desired locationafter completing the reading. See the thermostat manufac-turer’s instructions for adjusting the heat anticipator.b. When using an electronic thermostat, set the cycle rate for3 cycles per hr.CHECK SAFETY CONTROLSThe flame sensor, gas valve, and pressure switches were allchecked in the Start-up section as part of normal operation.1. Check primary limit control.This control shuts off the combustion control system andenergizes the circulating-air blower motor if the furnaceoverheats.The preferred method of checking the limit control is togradually block off the return air after the furnace has beenoperating for a period of at least 5 minutes. As soon as thelimit has shut off the burners, the return-air opening should beunblocked. By using this method to check the limit control, itcan be established that the limit is functioning properly andwill operate if there is a motor failure.2. Check draft safeguard switch.The purpose of this control is to cause safe shutdown of thefurnace during certain blocked vent conditions.a. Disconnect power to furnace and remove vent connectorfrom furnace flue collar. Be sure to allow time for ventconnector pipe to cool down before removing.b. Restore power to furnace and set room thermostat aboveroom temperature.Fig. 14—Burner Flame A89020Table 10—Speed SelectionCOLOR SPEED AS SHIPPEDWhite Common ComBlack High CoolYellow Med-High ParkBlue Med-Low High-Gas HeatRed Low* Low-Gas Heat* Continuous blower speedFig. 15—Amp Draw Check With AmmeterA80201R Y W G10 TURNSTHERMOSTAT SUBBASETERMINALS WITHTHERMOSTAT REMOVEDHOOK-AROUNDVOLT/AMMETEREXAMPLE: 5.0 AMPS ON AMMETER10 TURNS AROUND JAWS = 0.5 AMPS FOR THERMOSTAT SETTINGFROM UNIT 24-VOLTTERMINAL BLOCK16

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