Furnace not lighting

[SpencerA]

I need to trouble shoot my Furnace. Its not trying to light. I can see where it sparks and I don't see it trying. Where do I start?

 

[Snowmow]

Propane full and on?

 

[DUKHTR3]

What furnace brand and btu? Have u tried flipping the reset? Does the exhaust vent show any black soot?

Sent from my E6782 using Tapatalk

 

[SpencerA]

It is a Suburban 35K. Got it started the other night after several attemps. Stayed running for several hours. Next day same thing as it wouldn't start.

 

[4GR8X]

Greetings SpencerA,

I've had similar experiences. A quick Google search can provide some excellent trouble shooting tips. Copied and pasted below are some tips.

Offered for your consideration. Verify your DC battery voltage is greater than 12.8-ish volts. A strong battery is key to pass the sail switch test, which must be successfully completed before the igniter switch (clicking sound) engages.

SEQUENCE OF NORMAL OPERATION
The electronic ignition system is made up of three main parts: the module board, the
electrode assembly, and the electrode wire. The module board is the brain of the electronic
ignition system and it has several functions.
1. When the blower reaches approximately 75% of the normal rpm and sufficient airflow is
established, the sail switch engages and completes a 12-volt circuit through the limit
switch to the module board. (NOTE: Low voltage power supply will not provide
sufficient motor rpm to engage the sail switch.)
2. After a 12-18 second delay, 12-volt current will pass through the module board to the
solenoid valve. The current to the valve opens it and allows gas to the main burner,
simultaneously, the module board sends high voltage through the electrode wire to the
electrode assembly. The voltage seeks a ground between electrode and ground probe
and a spark occurs. The spark then ignites the main burner.
3. The module board also performs the lockout function in cases where the spark fails to
light the burner. When lockout occurs, the spark stops, the voltage from the module
board to the gas valve is discontinued, and the valve closes. The unit will remain in
lockout and the blower will continue to run until the thermostat is turned off. Turning
the thermostat off disengages the lockout function of the module board. After the
blower has stopped, the ignition sequence can be started again.

Hope this helps, good luck.

Craig.

 

[SpencerA]

Greetings SpencerA,

I've had similar experiences. A quick Google search can provide some excellent trouble shooting tips. Copied and pasted below are some tips.

Offered for your consideration. Verify your DC battery voltage is greater than 12.8-ish volts. A strong battery is key to pass the sail switch test, which must be successfully completed before the igniter switch (clicking sound) engages.

SEQUENCE OF NORMAL OPERATION
The electronic ignition system is made up of three main parts: the module board, the
electrode assembly, and the electrode wire. The module board is the brain of the electronic
ignition system and it has several functions.
1. When the blower reaches approximately 75% of the normal rpm and sufficient airflow is
established, the sail switch engages and completes a 12-volt circuit through the limit
switch to the module board. (NOTE: Low voltage power supply will not provide
sufficient motor rpm to engage the sail switch.)
2. After a 12-18 second delay, 12-volt current will pass through the module board to the
solenoid valve. The current to the valve opens it and allows gas to the main burner,
simultaneously, the module board sends high voltage through the electrode wire to the
electrode assembly. The voltage seeks a ground between electrode and ground probe
and a spark occurs. The spark then ignites the main burner.
3. The module board also performs the lockout function in cases where the spark fails to
light the burner. When lockout occurs, the spark stops, the voltage from the module
board to the gas valve is discontinued, and the valve closes. The unit will remain in
lockout and the blower will continue to run until the thermostat is turned off. Turning
the thermostat off disengages the lockout function of the module board. After the
blower has stopped, the ignition sequence can be started again.

Hope this helps, good luck.

Craig.

Thanks, I'll look into that. I just replaced the module. I'll look at power but its plugged into my garage outlet so I'm pretty sure that isn't the issue. I thought I read somewhere that one of the services they provide is a cleaning of a particular area that can cause this. I'll do some more research online.

 

[griffin86]

Not sure if you fixed it. My problem was too low of voltage. If it runs for a minute and shuts off, the voltage is too low.