WHITE-RODGERS

50E47 - 50F47 Hot Surface Ignition Modules

TROUBLESHOOTING

GENERAL INFORMATION

The following information will provide you with a systematic procedure for isolating equipment problems. This information is intended for use by qualified electricians or servicemen. High voltage is present in these systems and electrical shock hazard is present. Extreme caution must be used when working on the appliance.

The following test equipment is required to troubleshoot a system with a minimum of time and effort:

• Volt-Ohm Meter - for measuring voltage and resistance.
• Precision Micro Ammeter - For Checking Flame Sensor Output and Location.
• Pressure Gauge - Low Scale - For Checking Gas Pressure.

The 50E47; 50F47 Modules contain no serviceable parts. Replacements should be of the exact model and type to prevent flame roll-out, damage and possible injury.

DIAGNOSTICS

Some of the models are equipped with a Diagnostic Light and have self diagnostic capabilities

FLASH ON-OFF - On startup, the light on the module will FLASH ONCE, indicating that the control is functional.

STEADY LIGHT - If the light is ON CONTINUOUSLY, the fault is liable to be internal to the module. To make sure, interrupt the line or 25 volt thermostat power for a few seconds and then restore it. If an internal fault is indicated again, the control should be replaced.

FLASHING LIGHT - A FLASHING LIGHT indicates that the problem is most likely in the external components or wiring. Follow the preliminary steps if this is the case.

PRELIMINARY STEPS

The following four steps must be performed first before any other troubleshooting is done.

1. 1) Disconnect electrical power to the system at the main fuse or circuit breaker panel.
2. 2) Remove the draft shield if necessary to gain access to the ignitor.
3. 3) Visually inspect equipment for apparent damage. Check wiring for loose connections.
4. 4) Check for Reversed Polarity. (HSI models with diagnostic light are extremely polarity sensitive and may lock out if 120 volt service wiring is reversed).

• Disconnect the ignitor socket from the wiring harness. Connect an AC voltmeter across the terminal connected to the white wire and chassis ground.
• Re-connect the electric power to the system. If NO voltage exists, then the polarity is correct. Proceed to the next step. If voltage is present between the terminal connected to the white wire and the chassis ground, the main power supply lines are improperly connected to the appliance. (Reversed Polarity). Again disconnect the electric power from the system; then reverse the incoming line voltage leads and repeat this step to insure that NO voltage exists. When the polarity is determined to be correct, proceed to the next step.
• Re-connect the ignitor socket to the wiring harness. Re-check the system for proper operation.

If neither apparent damage, loose connections nor reversed polarity is the problem, then proceed to the VISUAL CHECK CHARTS that may help determine the problem.

THE VISUAL CHECK CHARTS

There are three visual checks that can be made to determine proper system operation.

1) The ignitor will warm up and glow red . If this is the case, see CHART 1

2) The main burner flame will ignite. If this is the case, see CHART 2

3) The main burner flame will continue to burn after the ignitor is turned off. If this is the case, see CHART 3

OTHER HSI TROUBLESHOOTING TIPS

See the Wistco Tips page for a discussion on Flame Rectification and Sensing problems.