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 39 page image

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 66 seconds afterthe gas 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 thehumidifier terminal HUM. The inducer motor IDM willremain energized for a 15-second post-purge period. Theblower motor BLWM and air cleaner terminal EAC-1 willremain energized for 90, 120, 150, or 180 seconds (depend-ing on the blower-OFF delay selection). The furnacecontrol CPU is factory-set for a 120-second blower-OFFdelay.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.To Begin Component Self-Test:ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in electrical shock,personal injury, or death.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.1. Remove blower access door.2. Disconnect the thermostat R lead from furnace control.3. Manually close blower door switch.4. For approximately 2 sec, short (jumper) the C OM-24v terminalon control to the TEST/TWIN 3/16-inch quick-connect termi-nal on control until the LED goes out. Remover jumper fromterminals. (See Fig. 33.)NOTE: If TEST/TWIN and C OM-24v terminals are jumperedlonger than 2 sec, LED will flash rapidly and ignore componenttest request.Component test sequence is as follows:a. LED will display previous status code 4 times.b. Inducer motor starts and continues to run until Step g ofcomponent test sequence.c. After 7 seconds the hot surface igniter is energized for 15sec, then off.d. Blower motor operates on HEAT speed for 10 sec.e. Blower motor operates on COOL speed for 10 sec.f. Inducer motor stops.5. Reconnect R lead to furnace control, remove tape from blowerdoor switch, and re-install blower door.39