Carrier 58CTA Installation And Service Instructions Manual

Also see for 58CTA: Product data Installation, start-up, operating and service and maintenance instructions

Carrier 58CTA Installation And Service Instructions Manual Manual pdf 40 page image

b. Turn Dip switch 2 and 3 ON or OFF for desired blower offdelay. (See Table 12 and Fig 32.)10. Set thermostat heat anticipator.a. Mechanical thermostat—Set thermostat heat anticapator tomatch the amp draw of the electrical components in theR-W/W1 circuit. Accurate amp draw readings can beobtained at the wires normally connected to thermostatsubbase terminals, R and W. The thermostat anticipatorshould NOT be in the circuit while measuring current.(1.) Set LHT switch on furnace control board to ON.(2.) Remove thermostat from sub-base or from wall.(3.) Connect an amp meter as shown in Fig. 54 across theR and W subbase terminals or R and W wires at wall.(4.) Record amp draw across terminals when furnace is inlow heat and after blower starts.(5.) Set heat anticipator on thermostat per thermostatinstructions and install on subbase or wall.(6.) Turn LHT switch OFF.(7.) Install blower access door.b. Electronic thermostat: Set cycle rate for 3 cycles per hr.11. Set airflow CFM for coolingSelect the desired blower motor speed lead for coolingairflow. See Table 5-Air Delivery-CFM (With Filter). SeeTable 11 for lead color identification.Step 4—Check Safety ControlsThe flame sensor, gas valve, and pressure switch were all checkedin the Start-up procedure section as part of normal operation.1. Check Main Limit Switch(es)This control shuts off combustion system and energizesair-circulating blower motor, if furnace overheats. By usingthis method to check limit control, it can be established thatlimit is functioning properly and will operate if there is arestricted return-air supply or motor failure. If limit controldoes not function during this test, cause must be determinedand corrected.a. Run furnace for at least 5 minutes.b. Gradually block off return air with a piece of cardboard orsheet metal until the limit trips.c. Unblock return air to permit normal circulation.d. Burners will re-light when furnace cools down.2. Check draft safeguard switch.The purpose of this control is to cause the safe shutdown of thefurnace during certain blocked vent conditions.a. Verify vent pipe is cool to the touch.b. Disconnect power to furnace and remove vent connectorfrom furnace vent elbow.c. Restore power to furnace and set room thermostat aboveroom temperature.d. After normal start-up, allow furnace to operate for 2minutes, then block vent elbow in furnace 80 percent ofvent area with a piece of flat sheet metal.e. Furnace should cycle off within 2 minutes. If gas does notshut off within 2 minutes, determine reason draft safeguardswitch did not function properly and correct condition.f. Remove blockage from furnace vent elbow.g. Switch will auto-reset when it cools.h. Re-install vent connector.NOTE: Should switch remain open longer than 3 minutes,furnace control board will lockout the furnace for 3 hours. To resetfurnace control board, turn thermostat below room temperature orfrom HEAT to OFF and turn 115-v power OFF, then back ON.3. Check Pressure Switch(es)This control proves operation of the draft inducer blower.a. Turn off 115-v power to furnace.b. Disconnect inducer motor lead wires from wire harness.c. Turn on 115-v power to furnace.d. Set thermostat to ″call for heat″ and wait 1 minute. Whenpressure switch is functioning properly, hot surface ignitershould NOT glow and control diagnostic light flashes astatus code 32. If hot surface igniter glows when inducermotor is disconnected, shut down furnace immediately.e. Determine reason pressure switch did not function properlyand correct condition.f. Turn off 115-v power to furnace.g. Reconnect inducer motor wires, replace outer door, andturn on 115-v power.h. Blower will run for 90 seconds before beginning the callfor heat again.i. Furnace should ignite normally.Step 5—Checklist1. Put away tools and instruments. Clean up debris.2. Verify that switches for LHT and OFF-DELAY are blowerOFF-DELAY are selected as desired.3. Verify that blower and burner access doors are properlyinstalled.4. Cycle test furnace with room thermostat.5. Check operation of accessories per manufacturer’s instruc-tions.6. Review User’s Guide with owner.7. Attach literature packet to furnace.Fig. 54—Amp Draw Check With AmmeterA96316R Y W G10 TURNSTHERMOSTAT SUBBASETERMINALS WITHTHERMOSTAT REMOVED(ANITICIPATOR, CLOCK, ETC.,MUST BE OUT OF CIRCUIT.)HOOK-AROUNDAMMETEREXAMPLE: 5.0 AMPS ON AMMETER10 TURNS AROUND JAWS = 0.5 AMPS FOR THERMOSTATANTICIPATOR SETTINGFROM UNIT 24-VCONTROL TERMINALS38→→