TROUBLESHOOTING PROCEDURE - ELECTRONIC IGNITION SYSTEM

START

Turn Off Gas Supply.

Ensure Valve Switch Is In ON Position.

Disconnect Control Harness.

• Set Thermostat To Call For Heat.

Insert A

End View of Control Harness Connector

24 Volt Hot

24 Volt

Common

 

24Volt Switched

Check For Damaged or Missing

Terminals in Connector

Insert B

Igniter Terminals

Igniter will cycle off and

1 back on once during the 90 second ignition trial. All voltage measurements must be taken while the igniter is powered.

Check for proper volt- age at control harness

2

(see insert A). Voltage NO

should be 24V between

 

 

 

thermostat or pressure

 

switch and 24V common

 

and 24V hot.

 

 

 

YES

 

 

 

 

Plug control harness into valve. Wait for internal check delay.

• Igniter warms up and glows

 

NO

red.

 

 

 

 

 

 

 

 

 

 

 

 

 

1

YES

 

 

 

 

 

 

 

 

 

 

NO

• Turn on gas supply.

 

 

• Pilot burner lights.

 

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Main valve opens and main

 

NO

 

burner lights.

 

 

 

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

 

 

• System Is okay.

 

 

 

 

 

 

 

 

 

 

 

When measuring voltage

2at connections, use care to ensure terminals are not damaged.

CHECK

Line voltage power

Low voltage transformer

Limit controller

Thermostat

Wiring

1• With pilot burner cable con- nected, measure voltage at valve HSI element output. 24V

2nominal. (See insert B)

YES

Replace igniter/flame rod assembly.

YES

Check that pilot gas is flowing. Wait to ensure pilot gas tubing is purged. Recycle call for heat if necessary.

YES

Measure voltage between 24V hot and 24V common leads to valve control. Must measure at least 19.5 VAC with igniter powered (see insert A). To identify proper lead, this check must be done with the valve control con- nected and igniter powered.

YES

Replace Pilot Assembly.

Check that pilot flame makes good contact with pilot burner flame rod.

Check for good electrical connection through the pilot tubing.

If both of the above are good, replace igniter/flame rod assembly.

YES

Cycle thermostat off and back on.

Main burner lights.

NO

NO

NO

NO

• Replace valve.

Replace valve.

Check transformer and line volt supply.

• Replace valve.

24

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

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Milwaukee LMDVT-3328CNM manual Troubleshooting Procedure Electronic Ignition System, Igniter will cycle off