Carrier 58DXT Operating Instructions Manual

Also see for 58DXT: User's information manual Service and maintenance instructions

Contents

Carrier 58DXT Operating Instructions Manual Manual pdf 14 page image

pressure sufficiently, high-heat pressure switch HPS opens.The low-heat gas valve solenoid GV remains energized aslong as low-heat pressure switch LPS remains closed.Blower motor BLWM switches speed for low-gas heat 5sec after R-W2 circuit opens.3. Cooling Modea. Single-Speed Cooling Outdoor Unit(See Fig. 11 for thermostat connections.)(1.) The thermostat closes R to G-and-Y circuits. TheR-Y circuit starts outdoor unit, and R to G-and-Ycircuits start furnace blower motor BLWM on high-cool speed.(2.) The EAC terminals EAC-1 and EAC-2 are energizedwith 115v when blower motor BLWM is operating.(3.) When thermostat is satisfied, R to G-and-Y circuitsare opened. The outdoor unit stops, and furnaceblower motor BLWM continues operating on high-cool speed for an additional 90 sec.b. Two-Speed Cooling Outdoor Unit(See Fig. 12 for thermostat connections.)(1.) The thermostat closes R to G-and-Y1 circuits for lowcooling or closes R to G-and-Y1-and-Y/Y2 circuitsfor high cooling. The R-Y1 circuits start outdoor uniton low-cooling speed, and R-G circuit starts furnaceblower motor BLWM on low-cooling speed (samespeed as for low-gas heat). The R to Y1-and-Y2circuits start outdoor unit on high-cooling speed, andR to G-and-Y2 circuits start furnace blower motorBLWM on high-cooling speed.NOTE: Y1 is not located on furnace control, but is found inoutdoor 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 blower motor BLWM is operating oneither cooling speed.(3.) When thermostat is satisfied, R to G-and-Y1 orR to G-and-Y1-and-Y/Y2 circuits open. The outdoorunit stops, and furnace blower continues operating oncooling speed for an additional 90 sec.4. Continuous Blower Modea. When R to G circuit is closed by thermostat, blower motorBLWM operates on low-gas-heat speed (identical to low-cool speed). Terminals EAC-1 and EAC-2 are energizedwith 115v as long as blower motor BLWM is energized.b. During "call for heat," blower motor BLWM stops duringignitor warm-up (17 sec), ignition (7 sec), and blower ondelay (45 sec), allowing furnace heat exchangers to heat upquickly.(1.) The blower motor BLWM reverts to continuousblower speed after heating cycle is completed. Inhigh-gas heat, furnace control CPU holds blowermotor BLWM at high-gas-heat speed during selectedblower off delay period before reverting to continuousblower speed.(2.) When thermostat "calls for low cooling," blowermotor BLWM continues to operate on low-cool speed.When thermostat is satisfied, blower motor BLWMcontinues on continuous blower speed.(3.) When thermostat "calls for high cooling," blowermotor BLWM operates on high-cool speed. Whenthermostat is satisfied, blower motor BLWM operatesan additional 2 sec on high-cool speed before revertingback to continuous blower speed.(4.) When R to G circuit is opened, blower motor BLWMcontinues operating for an additional 90 sec if no otherfunction requires blower motor BLWM operation.5. Heat PumpNOTE: An accessory interface kit is required with single-speedheat pumps. See interface kit Installation Instructions for single-speed heat pump thermostat and interface connections. No inter-face kit is needed for 2-speed heat pumps. See 2-speed heat pumpInstallation Instructions for thermostat connections.a. Single-Speed Heat Pump Cooling(1.) The thermostat and interface kit close R to G-and-Y/Y2 circuit to start furnace blower motor BLWM onhigh-cooling speed. (Y/Y2 input to furnace control isnecessary to provide adequate cooling airflow.)(2.) The EAC terminals EAC-1 and EAC-2 are energizedwith 115v when blower motor BLWM is operating.(3.) When thermostat is satisfied, furnace blower motorBLWM continues operating on high-cooling speed foran additional 90 sec.b. Two-Speed Heat Pump Cooling(1.) The thermostat R to G circuits start furnace blowermotor BLWM on low-cooling speed. ThermostatR to G-and-Y/Y2 circuits start furnace blower motorBLWM on high-cool speed.NOTE: The furnace control CPU controls blower motor BLWMspeed by sensing only G (for low-cooling speed) and Y2 (forhigh-cooling speed).(2.) The EAC terminals EAC-1 and EAC-2 are energizedwith 115v when blower motor BLWM is operating oneither cooling speed.(3.) When thermostat is satisfied, furnace blower motorBLWM continues operating on cooling speed for anadditional 90 sec.c. Single-Speed Heat Pump Heating(1.) The thermostat and accessory interface kit R to G-and-Y/Y2 circuits start furnace blower motor BLWMon heat pump high-heat speed (identical to high-coolspeed).(2.) The EAC terminals EAC-1 and EAC-2 are energizedwith 115v when blower motor BLWM is operating.(3.) When thermostat is satisfied, furnace blower motorBLWM continues operating on heat pump high-heatspeed for an additional 90 sec.d. Two-Speed Heat Pump Heating(1.) The thermostat closes R to G circuit for low heat andstarts furnace blower motor BLWM on heat pumplow-heat speed (identical to low-cooling speed). Clos-ing R-Y/Y2 circuit to furnace provides blower motorBLWM heat pump high-heat speed.NOTE: The furnace control CPU controls blower motor BLWMspeed by sensing only G (for heat pump low-heat speed) and Y2(for heat pump high-heat speed).(2.) The EAC terminals EAC-1 and EAC-2 are energizedwith 115v when blower motor BLWM is operating oneither heating speed.(3.) When thermostat is satisfied, R to G or R to G-and-Y2 circuits are opened. After opening R to G-and-Y214