Carrier 59SP5A Installation, Start-up, Operating And Service And Maintenance Instructions

Also see for Infinity 59TN6A: Installation, start-up, operating and service and maintenance instructions Installation, start-up, operating and service and maintenance instructions Product data Product data Installation, start-up, operating and service and maintenance instructions

73SEQUENCE OF OPERATIONNOTE: Furnace control must be grounded for proper operation orcontrol will lock out. Control is grounded through green/yellowwire routed to gas valve and manifold bracket screw. Using theschematic diagram in Fig. 63, follow the sequence of operationthrough the different modes. Read and follow the wiring diagramvery carefully.NOTE: If a power interruption occurs during a call for heat (W),the control will start a 90--sec blower--only ON period two sec afterpower is restored, if the thermostat is still calling for gas heating.The Amber LED light will flash code 12 during the 90--sec period,after which the LED will be ON continuous, as long as no faultsare detected. After the 90--sec period, the furnace will respond tothe thermostat normally.The blower door must be installed for power to be conductedthrough the blower door interlock switch ILK to the furnacecontrol CPU, transformer TRAN, inducer motor IDM, blowermotor BLWM, hot--surface igniter HSI, and gas valve GV.1. Heating(See Fig. 35 and 36 for thermostat connections.)The wall thermostat “calls for heat,” closing the R--to--Wcircuit. The furnace control performs a self--check, verifiesthe pressure switch contacts LPS and HPS are open, andstarts the inducer motor IDM.a. Inducer Prepurge Period-- As the inducer motor IDMcomes up to speed, the low pressure switch contacts LPSclose to begin a 15--sec prepurge period. The high pressureswitch contacts HPS are ignored until one minute after thegas valve closes.b. Igniter Warm--Up-- At the end of the prepurge period, theHot--Surface igniter HSI is energized for a 17--sec igniterwarm--up period.c. Trial--for--Ignition Sequence-- When the igniter warm--up period is completed, the main gas valve relay contactsGVR close to energize the gas valve GV, the gas valveopens, and 24 vac power is supplied for a field--installedhumidifier at the HUM terminal. The gas valve GV permitsgas flow to the burners where it is ignited by the HSI. Fivesec after the GVR closes, a 2--sec flame proving period be-gins. The HSI igniter will remain energized until the flameis sensed or until the 2--sec flame proving period begins.d. Flame--Proving-- When the burner flame is proved at theflame--proving sensor electrode FSE, the furnace controlCPU begins the blower--ON delay period and continues tohold the gas valve GV open. If the burner flame is notproved within two sec, the control CPU will close the gasvalve GV, and the control CPU will repeat the ignition se-quence for up to three more Trials--For--Ignition before go-ing to Ignition--Lockout. Lockout will be reset automatic-ally after three hours or by momentarily interrupting 115vac power to the furnace, or by interrupting 24 vac powerat SEC1 or SEC2 to the furnace control CPU (not at W, G,R, etc.).If flame is proved when flame should not be present, thefurnace control CPU will lock out of Gas--Heating modeand operate the inducer motor IDM until flame is no longerproved.e. Blower--On Delay-- If the burner flame is proven, theblower motor is energized on HEAT speed 25 sec after thegas valve GV is energized.Simultaneously, the electronic air cleaner terminal EAC--1is energized and remains energized as long as the blowermotor BLWM is energized.f. Blower--Off Delay-- When the thermostat is satisfied, theR--to--W circuit is opened, de--energizing the gas valve GV,stopping gas flow to the burners, and de--energizing the hu-midifier terminal HUM. The inducer motor IDM will re-main energized for a 15--sec post--purge period. Theblower motor BLWM and air cleaner terminal EAC--1 willremain energized for 90, 120, 150, or 180 sec (dependingon the blower--OFF delay selection). The furnace controlCPU is factory--set for a 120--sec blower--OFF delay.2. Cooling ModeThe thermostat “calls for cooling.”a. Single--Speed Cooling(See Fig. 35 and 36 for thermostat connections)The thermostat closes the R--to--G--and--Y circuits. TheR--to-- Y circuit starts the outdoor unit, and the R--to--G--and--Y/Y2 circuits start the furnace blower motorBLWM on COOL speed.The electronic air cleaner terminal EAC--1 is energizedwith 115 vac when the blower motor BLWM is operating.When the thermostat is satisfied, the R--to--G--and--Y cir-cuits are opened. The outdoor unit will stop, and the fur-nace blower motor BLWM will continue operating on theCOOL speed for an additional 90 sec. Jumper Y/Y2 toDHUM to reduce the cooling off--delay to 5 sec. (See Fig.35.)b. Two--Speed Cooling(See Fig. 35 and 36 for thermostat connections.)The thermostat closes the R--to--G--and--Y1 circuits forlow--cooling or closes the R--to--G--and--Y1--and--Y2 cir-cuits for high--cooling. The R--to--Y1 circuit starts the out-door unit on low--cooling speed, and the R--to--G--and--Y1circuit starts the furnace blower motor BLWM on low--coolspeed (same speed as FAN). The R--to--Y1--and--Y2 cir-cuits start the outdoor unit on high--cooling speed, and theR--to--G and-- Y/Y2 circuits start the furnace blower motorBLWM on COOL speed.The electronic air cleaner terminal EAC--1 is energizedwith 115 vac whenever the blower motor BLWM is operat-ing.When the thermostat is satisfied, the R--to--G--and--Y1 orR--to--G--and--Y1 and Y2 circuits are opened. The outdoorunit stops, and the furnace blower BLWM and electronicair cleaner terminal EAC--1 will remain energized for anadditional 90 sec. Jumper Y1 to DHUM to reduce the cool-ing off--delay to 5 sec. (See Fig. 35.)3. Dehumidification Mode(See Fig. 35 and 36 for Thermidistat connections.)The dehumidification output, D or DHUM from a thermo-stat should be connected to the furnace control thermostatterminal DHUM. When there is a dehumidify demand, theDHUM input is activated, which means 24 vac signal is re-moved from the DHUM input terminal. In other words, theDHUM input logic is reversed. The DHUM input is turnedON when no dehumidify demand exists. Once 24 vac is de-tected by the furnace control on the DHUM input, dehumid-ification capability is activated. If the DHUM is removedfor more than 48 hr, the furnace control reverts back tonon--dehumidification mode.The cooling operation described in item 2. above also ap-plies to operation with a Thermidistat. The exceptions arelisted below:a. When the R--to--G--and--Y1 circuit is closed and there is ademand for dehumidification, the furnace blower motorBLWM will continue running at low--cool speed (samespeed as FAN).b. When the R--to--G--and--Y/Y2 circuit is closed and thereis a demand for dehumidification, the furnace blower mo-tor BLWM will drop the blower speed from COOL toHEAT for a maximum of 10 minutes before reverting backto COOL speed. If there is still a demand for dehumidifica-59SP5A