Carrier 59CU5A Installation, Start-up, Operating And Service And Maintenance Instructions

59CU5A: Installation, Start-up, Operating and Service and Maintenance InstructionsManufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.66Troubleshooting Guide (Continued)A11326CTroubleshooting Guide (Continued)25 INVALID MODEL SELECTION ORSETUP ERROR – If status code 25 onlyflashes 4 times on power-up the control ismissing its model plug PL4 and isdefaulting to the model selection stored inmemory. If status code 25 flashescontinuously it could indicate any of thefollowing:- Model plug PL4 is missing and there isno valid model stored in permanentmemory. This will happen if you forgetto install the model plug PL4 on aservice replacement control.- Thermostat call with SW1-1 ON.- Thermostat call with SW1-6 ON.- SW1-1 and SW1-6 both ON.- Two different furnace models twinned.- Service replacement control is incorrect.Need non-modulating board withsoftware version V17 or later.31 HIGH-HEAT PRESSURE SWITCH ORRELAY DID NOT CLOSE ORREOPENED - Check for:- Control relay may be defective.- Gas valve is miswired.- See status code 32.41 BLOWER MOTOR FAULT – Indicates theblower failed to reach 250 RPM or theblower failed to communicate within theprescribed time limits. Thirty secondsafter being turned ON or ten secondsduring steady-state operation. Turn poweroffand check the following items firstbefore proceeding to the next step.- Rubbing blower wheel.- Loose blower wheel.- Wiring from furnace control to blowermotor.Remove the R thermostat connection fromthe furnace control, disconnect bothconnectors from the blower motor PL13and PL14. Does the blower wheel turnfreely?Replace the blower control module attached tothe blower motor. Follow the instructions withthe blower control module to make sure theentire blower motor does not need to bereplaced.Turn power back on. Is there 115VAC atPL14-5 and PL14-4?You have an open wire or badterminal on either the BLACK orWHITE power leads betweenthe furnace control and theblower motor. If you have apower choke disconnect it andcheck continuity.YESYESNONOIs there 12-VDC at PL13-7 RED (+) andPL13-1 GREEN (-)?YESNOIs there 12-VDC at PL3-1 RED (+) andPL3-2 GREEN (-)?Replace the furnace control.NOYou have an open wire or badterminal on either the RED orGREEN wire between thefurnace control and the blowermotor.YESIs there 5-VDC at PL13-16 YELLOW (+)and PL13-1 GREEN (-)?Is there 5-VDC at PL3-3YELLOW (+) and PL3-2GREEN (-)?NONOYou have an open wire or badterminal on the YELLOW wirebetween the furnace control andthe blower motor.YESYESThe voltage just measured should bevery stable and should not fluctuate morethan .02-VDC. If the voltage fluctuatesmore than this get a different voltmeterbefore proceeding.Turn power off, disconnect PL13 andPL14 from the blower motor, then turnpower back on. Connect a DC voltmeteracross PL13-16 BLUE (+) and PL13-1GREEN (-). The voltage should be near0-VDC but it will fluctuate briefly severaltimes a second. If you have an analogvoltmeter the needle will briefly go highseveral times a second. If you have adigital voltmeter with a bar graph it willshow a large change in magnitude on thebar graph several times a second. If youhave a standard digital voltmeter it willshow a brieffl uctuation in voltage and themagnitude may vary depending on thevoltmeter used.Does the voltage fluctuate as described in theprevious step?Connect a DC voltmeter across PL3-4 BLUE(+) and PL3-2 GREEN (-). Does the voltagefluctuate as described two steps back?You have an open wire or bad terminal on theBLUE wire between the furnace control and theblower motor.NOReplace the furnace control.YESTurn power off, reconnect PL13 andPL14 to the blower motor, then turnpower back on. Connect a DC voltmeteracross PL3-3 YELLOW (+) and PL3-2GREEN (-). Does the voltage fluctuatemore than it did in the previous step?NOYESYESNOReplace the blower control module attached tothe blower motor. Follow the instructions withthe blower control module to make sure theentire blower motor does not need to bereplaced.