Thermo Products CHX3-75N, CDX3-75N, CHX3-125N, CDX3-125N, CHX3-100N, CDX3-100N Troubleshooting Guide

All installations and services must be performed by qualified service personnel.

TROUBLESHOOTING GUIDE

THE SYSTEM IS STARTED BY SETTING THE THERMOSTAT TO CALL FOR

HEAT. THE FOLLOWING SHOULD HELP ESTABLISH THE TYPE OF

MALFUNCTION OR DEVIATION FROM THE NORMAL OPERATION.

NOTE: REFER TO PAGE 48 FOR DEFINITION OF DIAGNOSTIC LEDS.

TO USE THIS DIAGRAM, YOU JUST NEED TO FOLLOW THE INSTRUCTIONS IN THE BOXES.

SET THERMOSTAT TO CALL FOR HEAT

(MAKE CERTAIN ROOM TEMPERATURE IS BELOW THERMOSTAT SETTING)

IS THE INDUCER

BLOWER OPERATING?

NO

IS THERE 120 VOLTS ACROSS "L1" AND "NEUTRAL" AT THE 50V51-843 CONTROL MODULE?

YES

NO

CHECK INPUT POWER, DOOR INTERLOCK, SERVICE SWITCH AND FUSES

IS THERE 24 VOLTS ACROSS "TH" & "TR"

AT THE INTEGRATED CONTROL MODEL 50V51-843?

YES

YES

IS THERE 24V

ACROSS R AND B/C

YES

NO

NO

CHECK 115 VOLT

CONNECTIONS. IF OK,

REPLACE TRANSFORMER

CHECK FUSE ON

W/R 50V51-843

IS THERE 24 VOLTS YES

ACROSS "R" AND "W1"?

NO

IS THERE LINE VOLTAGE
ACROSS INDUCER POWER
TERMINALS "IND HI" TO		NO
"IND N" OR "IND LO" TO
"IND N" AT THE 50V51-843
CONTROL?
	YES

CHECK WIRING TO INDUCER

AND IF OK, REPLACE

INDUCER ASSEMBLY.

CHECK WIRING TO THERMOSTAT. IF OK, REPLACE THERMOSTAT.

REPLACE THE

50V51-843 CONTROL.

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