IS INDUCER RUNNING

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

NO

NO

CHECK CONTACTS ON LOW FIRE PRESSURE SWITCH AND FOR BLOCKAGE IN FLUE. IF OK, REPLACE DUAL PRESSURE SWITCH.

IS THERE VOLTAGE ACROSS

HOT SURFACE IGNITOR

TERMINALS "IGN" & "IGN N" AT THE 50V51-843 CONTROL AFTER 17 SECOND PREPURGE?

YES

CHECK WIRING TO HOT

SURFACE IGNITOR AND

IF OK, REPLACE HOT

SURFACE IGNITOR

ASSEMBLY

REPLACE THE

50V51-843 CONTROL.

 

 

YES

 

 

 

 

IS THE HIGH LIMIT,

NO

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.

AFTER HOT SURFACE

IGNITOR WARM-UP,

DOES GAS VALVE OPEN?

YES

AFTER GAS VALVE

OPENS, DO THE

BURNERS IGNITE?

NO

NO

 

CHECK ACROSS "MVL" AND

 

 

"MV COM" TERMINALS ON

 

 

50V51-843 CONTROL FOR 24

NO

 

VOLTS DURING THE 4 SECOND

 

 

 

FLAME PROVING PERIOD

 

 

AFTER IGNITOR WARM-UP.

 

 

IS THERE 24 VOLTS?

 

 

 

 

 

 

 

 

YES

 

 

 

 

 

 

IS COLLECTOR BOX

NO

PRESSURE SWITCH CLOSED?

YES

CHECK WIRING TO GAS

VALVE AND IF OK,

REPLACE GAS VALVE.

CHECK FOR PROPER LINE

AND MANIFOLD PRESSURE.

REFERENCE GAS PRESSURE

CHART PAGE 31.

REPLACE THE

50V51-843 CONTROL.

CHECK DRAIN FOR BLOCKAGE WATER TRAPPED IN HOSE, REPLACE SWITCH.

YES

OK

51

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Image 57
Thermo Products chx-3 75n, 100n, 125n operation manual Is Inducer Running On Low Speed? Yes Does The Hot