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

Also see for 58TMA: Install and operation instructions Service and maintenance instructions User's information manual User's information manual

Contents

Carrier 58TMA Installation, Start-up, And Operating Instructions Manual Manual pdf 12 page image

d. Flame-proving—When the burner flame is proved at theflame-proving sensor electrode FSE, the control CPUbegins the blower on delay period and continues to hold thegas valve GV open. If the burner flame is not proved within2 sec, the control CPU closes the gas valve GV, and thecontrol CPU repeats the ignition sequence for up to 3 moretrials-for-ignition before going to ignition lockout. LOCK-OUT IS RESET AUTOMATICALLY after 3 hrs, or bymomentarily interrupting 115-v power to the furnace, or byinterrupting 24-v power at SEC1 or SEC2 to the controlCPU (not at W/W1, G, R, etc.). Opening the thermostatR-W circuit will not reset an ignition lockout.If flame is proved when flame should not be present, thecontrol CPU locks out of gas heating mode and operatesthe inducer motor IDM on high speed until flame is nolonger proved.e. Blower on delay—If the burner flame is proven, 45 secafter the gas valve GV is opened the blower motor BLWMis energized on the appropriate heating speed, low-gas-heator high-gas-heat speed. Simultaneously, the EAC terminalsEAC-1 and EAC-2 are energized with 115v and remainenergized as long as the blower motor BLWM is energized.f. Switching from low- to high-gas heat—If the furnacecontrol CPU switches from low-gas heat to high-gas heat,the control CPU switches the inducer motor IDM speedfrom low to high. The high-heat pressure switch relayHPSR closes. When the inducer motor IDM providessufficient pressure to close the high-heat pressure switchHPS, the high-heat gas valve solenoid GV is energized. Theblower motor BLWM switches speed for high-gas heat 5sec after the control CPU switches from low-gas heat tohigh-gas heat.g. Switching from high- to low-gas heat—The control CPUwill not switch from high-gas heat to low-gas heat whilethe thermostat R-W circuit is closed when a single-stagethermostat is used.h. Blower off delay—When the thermostat is satisfied, theR-W circuit is opened, de-energizing the gas valve GV,stopping gas flow to the burners, and de-energizing thehumidifier terminals HUM and Com. The inducer motorIDM remains energized for a 5-sec post-purge period. Theblower motor BLWM and EAC terminals EAC-1 andEAC-2 remain energized for 90, 135, 180, or 225 sec(depending on selection at blower off delay switches SW-3and SW-4). The furnace control CPU is factory set for a135-sec blower off delay.2. Non-Adaptive Heating Mode—Two-Stage Thermostat and2-Stage Heating(See Fig. 13 for thermostat connections.)NOTE: The low-heat-only switch SW-2 on selects the low-heat-only operation mode in response to closing the thermostatR-W/W1 circuit. When the high-heat-only switch SW-1 is off,closing the thermostat R to W1-and-W2 circuits is required forhigh-gas-heat operation. When the high-heat-only switch SW-1 ison, it always causes high-gas-heat operation when the R-W/W1circuit is closed, regardless of the setting of the low-heat-onlyswitch SW-2 and regardless of whether the R-W2 circuit is closedor open.The start-up and shutdown functions and delays described initem 1. above apply to the 2-stage heating mode as well,except for switching from low- to high-gas heat and viceversa.a. When the wall thermostat "calls for heat," the R-W/W1circuit closes for low-gas heat or the R to W1-and-W2circuits close for high-gas heat. The furnace control per-forms a self-check, verifies the low-heat and high-heatpressure switch contacts LPS and HPS are open, and startsthe inducer motor IDM in low speed or high speed asappropriate.b. Switching from low- to high-gas heat—If the thermostatR-W/W1 circuit for low-gas heat is closed and the R-W2circuit for high-gas heat closes, the control CPU switchesthe inducer motor IDM speed from low to high. Thehigh-heat pressure switch relay HPSR closes. When theinducer motor IDM provides sufficient pressure to closethe high-heat pressure switch HPS, the high-heat gas valvesolenoid GV is energized. The blower motor BLWMswitches speed for high-gas heat 5 sec after the R-W2circuit closes.c. Switching from high- to low-gas heat—If the thermostatR-W2 circuit for high-gas heat opens and the R-W/W1circuit for low-gas heat remains closed, the control CPUswitches the inducer motor IDM speed from high to low.The high-heat pressure switch relay HPSR opens to de-energize the high-heat gas valve solenoid GV. When theinducer motor IDM reduces pressure sufficiently, thehigh-heat pressure switch HPS opens. The low-heat gasvalve solenoid GV remains energized as long as thelow-heat pressure switch LPS remains closed. The blowermotor BLWM switches speed for low-gas heat 5 sec afterthe R-W2 circuit opens.3. Cooling Modea. Single-Speed Cooling Outdoor Unit(See Fig. 12 for thermostat connections.)(1.) The thermostat closes the R to G-and-Y circuits. TheR-Y circuit starts the outdoor unit, and the R toG-and-Y circuits start the furnace blower motorBLWM on high-cool speed.(2.) The EAC terminals EAC-1 and EAC-2 are energizedwith 115v when the blower motor BLWM is operat-ing.(3.) When the thermostat is satisfied, the R to G-and-Ycircuits are opened. The outdoor unit stops, and thefurnace blower motor BLWM continues operating onthe high-cool speed for an additional 90 sec.b. Two-Speed Cooling Outdoor Unit(See Fig. 13 for thermostat connections.)(1.) The thermostat closes the R to G-and-Y1 circuits forlow cooling or closes the R to G-and-Y1-and-Y/Y2circuits for high cooling. The R-Y1 circuits start theoutdoor unit on low-cooling speed, and the R-G circuitstarts the furnace blower motor BLWM on low-cooling speed (same speed as for low-gas heat). The Rto Y1-and-Y2 circuits start the outdoor unit on high-cooling speed, and the R to G-and-Y2 circuits startthe furnace blower motor BLWM on high-coolingspeed.NOTE: Y1 is not located on the furnace control, but is found inthe outdoor unit. The furnace control CPU controls blower motorBLWM speed by sensing only G for low-cooling speed and Y/Y2for high-cooling speed.(2.) The EAC terminals EAC-1 and EAC-2 are energizedwith 115v when the blower motor BLWM is operatingon either cooling speed.12