Daikin MPS025B - Troubleshooting - Furnace Operation and Safety; Furnace Operation and Safety Checks; Blower Motor and Airflow Troubleshooting


www.DaikinApplied.com 49 IM 972-2 • MAVERICK I ROOFTOP SYSTEMS
Figure 40 continued: Furnace Troubleshooting Chart
40 IM 862-1
NOTE: IF THE SYSTEM GOES INTO LOCKOUT, WAIT
30 SECONDS AND RESET THE SYSTEM.
• CHECK FLAME SENSOR POSITION AND CONDITION
• CLEAN FLAME SENSOR WITH STEEL WOOL
• CHECK FLAME SENSOR WIRES AND CONNECTIONS
• CHECK FOR 208-230 VAC ACROSS BLOWER
MOTOR TERMINALS ON CONTROL BOARD
• CHECK FOR LINE VOLTAGE AT LOAD SIDE OF
BLOWER CONTACT.
YES
YES
NO
MAIN BURNER FLAME SUSTAINED
YES
NO
INDOOR BLOWER MOTOR STARTS
AFTER 45 SECONDS
REPLACE SENSOR
NO
REPLACE INTEGRATED
CONTROL BOARD (IFC)
NO
REPLACE IGNITION
CONTROL
YES
REPLACE BLOWER
MOTOR
• CHECK FOR OPEN LIMIT
• CHECK FOR OPEN ROLL-OUT CONTROL
• CHECK FOR PROPER THERMOSTAT OPERATION
• REMOVE VALVE LEAD AT GAS VALVE
IF VALVE CLOSES, RECHECK THE THERMOSTAT
AND WIRING. IF OK, THEN REPLACE VALVE
YES
NO
SYSTEM RUNS UNTIL
CALL FOR HEAT ENDS
TROUBLESHOOTING ENDS
REPEAT PROCEDURE UNTIL TROUBLE FREE
OPERATION IS OBTAINED.
YES
NO
TURN THERMOSTAT OFF
VALVE SHUTS OFF
FLAME SHUTS OFF
YES
INDUCED DRAFT MOTOR STOPS
AFTER 5 SECOND POSTPURGE
YES
YES
• CHECK FOR DIRTY FILTERS
• CHECK FOR RESTRICTED
AIR-FLOW
CHECK FOR EXHAUST,
INTAKE OR HEAT
EXCHANGER BLOCKAGE
CLEAR BLOCKAGE AND
RESET CONTROL
YES
INDOOR BLOWER MOTOR STOPS
AFTER 90 SECONDS
YES
FURNACE STARTS ON LOW OR HIGH
FIRE. FURNACE SWITCHES TO LOW
FIRE AFTER 120 SECONDS WARMUP
IF THERMOSTAT IS CALLING FOR W1.
FURNACE WILL SWITCH TO HIGH
FIRE IF LOW FIRE DOES NOT SATISFY
THERMOSTAT DEMAND FOR HEAT
LOAD.
Figure 21: Furnace Troubleshooting Guide (Combination Heating and Cooling Units with Direct Spark Ignition) - continued