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

Also see for 58MSA Series: Service and maintenance instructions User manual Instruction manual Installation, start-up, and operating instructions Installation, start-up, and operating instructions

Carrier 58MSA Installation, Start-up, And Operating Instructions Manual Manual pdf 35 page image

2. Cooling Mode(See Fig. 30 for thermostat connections)The thermostat closes the R-to-G-and-Y circuits. The R-to-Ycircuit starts the outdoor unit, and the R-to-G and Y circuitsstart the furnace blower motor BLWM on COOL speed.The electronic air cleaner terminal EAC-1 is energized with115 vac when the blower motor BLWM is operating.When the thermostat is satisfied, the R-to-G-and-Y circuits areopened. The outdoor unit will stop, and the furnace blowermotor BLWM will continue operating on the COOL speed foran additional 90 seconds. Cut jumper J2 to reduce the coolingoff-delay to 5 seconds. (See Fig. 33.)3. Continuous Blower ModeWhen the R-to-G circuit is closed by the thermostat, theblower motor BLWM will operate on continuous-blowerspeed (same as HEAT speed). Terminal EAC-1 is energized aslong as the blower motor BLWM is energized.During ″a call for heat,″ the blower BLWM will stop duringigniter warm-up (17 seconds), ignition (7 seconds), andblower-ON delay (66 seconds), allowing the furnace heatexchangers to heat up more quickly, then restarts at the end ofthe blower-ON delay period at HEAT speed.In heating, the furnace control CPU will continue running theblower motor BLWM at HEAT speed after the selectedblower-OFF delay period is completed.When the thermostat ″calls for cooling″, the blower motorBLWM will operate at COOL speed. When the thermostat issatisfied, the blower motor BLWM will operate an additional90 seconds on COOL speed before reverting back to HEATspeed. Jumper J2 can be can be cut to reduce the coolingoff-delay to 5 seconds. (See Fig. 33.)When the R-to-G circuit is opened, the blower motor BLWMwill continue operating for an additional 5 seconds, if no otherfunction requires blower motor BLWM operation.4. Heat Pump ModeWhen installed with a heat pump, the furnace control auto-matically changes the timing sequence to avoid long bloweroff times during demand defrost cycles. When the R-to-W-and-Y or R-to-W-and-Y-and-G circuits are energized thefurnace control CPU will continue to turn on the blower motorBLWM at HEAT speed, and begin a heating cycle. Theblower motor BLWM will remain on until the end of theprepurge period, then shut off for 24 seconds then come backon at HEAT speed. When the W input signal disappears, thefurnace control begins a normal inducer post-purge period andthe blower switches to COOL speed after a 3 second delay. Ifthe R-to-W-and-Y-and-G signals disappear at the same time,the blower motor BLWM will remain on for the selectedblower-OFF delay period. If the R-to-W-and-Y signals disap-pear, leaving the G signal, the blower motor BLWM willcontinue running the blower motor BLWM at HEAT speedafter the selected blower-OFF delay period is completed.COMPONENT TESTNOTE: The furnace control component test allows all compo-nents to run for a short time; except the gas valve and humidifierterminal HUM are not energized for safety reasons. The EAC-1terminal is energized when the blower is energized. This featurehelps diagnose a system problem in case of a component failure.The component test feature will not operate if any thermostatsignal is present at the control and not until all time delays arecompleted.NOTE: Record the status code BEFORE opening the bloweraccess door and before shutting off power to the furnace. Openingthe blower access door will open the blower door switch and shutoff power within the furnace. When power to the furnace is shutoff by either method, the status code will be lost because the codeis not stored while power is removed for any reason.To Begin Component Self-Test:Blower access panel door switch opens 115-v power tocontrol center. No component operation can occur. Cautionmust be taken when manually closing this switch for servicepurposes. Failure to follow this warning could result inelectrical shock, personal injury, or death.1. Remove blower access door.2. Disconnect the thermostat R lead from furnace control.3. Manually close blower door switch.Fig. 42—Example of Field Drain AttachmentA94054OPEN STANDPIPE FORA/C ORHUMIDIFIERDRAINTEETO OPENDRAINFig. 43—Condensate Trap Heat Tape A93036CONDENSATE TRAPWIRE TIE(S)HEAT TAPE(3 WRAPS MINIMUM)35