Thermo Pride CDX1-100N Installation And Operation Manual page 50

All installations and services must be performed by qualified service personnel.
IS INDUCER RUNNING
ON LOW SPEED?
YES
DOES THE HOT
SURFACE IGNITOR
ENERGIZE AND GLOW?
YES
AFTER HOT SURFACE
IGNITOR WARM-UP,
DOES GAS VALVE OPEN?
YES
AFTER GAS VALVE
OPENS, DO THE
BURNERS IGNITE?
YES
CHECK CONTACTS ON LOW
FIRE PRESSURE SWITCH
NO
AND FOR BLOCKAGE IN FLUE.
IF OK, REPLACE DUAL
PRESSURE SWITCH.
IS THERE VOLTAGE ACROSS
HOT SURFACE IGNITOR
NO
TERMINALS "IGN" & "IGN N"
AT THE 50V61-143 CONTROL
AFTER 25 SECOND PREPURGE?
CHECK WIRING TO HOT
SURFACE IGNITOR AND
IF OK, REPLACE HOT
SURFACE IGNITOR
ASSEMBLY
CHECK ACROSS "MVL" AND
"MV COM" TERMINALS ON
50V61-143 CONTROL FOR 24
NO
VOLTS DURING THE 4 SECOND
FLAME PROVING PERIOD
AFTER IGNITOR WARM-UP.
IS THERE 24 VOLTS?
IS COLLECTOR BOX
PRESSURE SWITCH CLOSED?
CHECK WIRING TO GAS
VALVE AND IF OK,
REPLACE GAS VALVE.
CHECK FOR PROPER LINE
NO AND MANIFOLD PRESSURE.
REFERENCE GAS PRESSURE
CHART PAGE 31.
44
NO
YES
NO
YES
NO
YES
OK
REPLACE THE
50V61-143 CONTROL.
YES
IS THE HIGH LIMIT,
ROLL-OUT LIMIT, AND
AUX LIMIT ON
(CDX MODELS)
SWITCHES CLOSED?
NO
IF HIGH LIMIT OR
AUX LIMIT OPEN CHECK
FOR RESTRICTED
FILTERS OR DUCT WORK
IF ROLL-OUT SWITCH
OPEN INSPECT FLUE FOR
RESTRICTIONS.
REPLACE THE
50V61-143 CONTROL.
CHECK DRAIN FOR
BLOCKAGE WATER
TRAPPED IN HOSE,
REPLACE SWITCH.