We have a coleman model # dgaa077bdtb a single light flashing comes and shuts off furnace. this is our vacation home and are not to monitor it. this indicates a ignition faliure which seems inconsista

SOURCE: Coleman furnace -- fan runs, ingniter won't light,

Hi,
The chances are that the furnace was running when the power went out. This will cause the high limit switch to cutout and needs to be manually reset.
You will find that switch in the blower compartment near the blower. Usually somewher near the highest point of the cabinet.
Push the little red button firmly till it clicks.
When the power goes out while the furnace is running the heat builds up because the blower shuts down immediately and causes this limit switch to cut out.
If you have a electric tester you can also follow the low voltage circuit till you find the open switch. Ther is usually a wiring schematic on the door cover of most furnaces.

I hope that this will help you to solve your problem!

Thanks for using Fixya!!

Heatman101

SOURCE: Coleman DGAA056BDTB mobile home furnace

try national energy for on line parts

SOURCE: no problem-just want info

This unit is electronic ignition

SOURCE: Coleman furnace -- fan runs, ingniter won't light,

My furnace did not have a reset switch on that particular limiter. I unpugged the switch, it had 2 wires, waited 15 seconds or so and then plugged it back in . Turned the furnace back on and the limiter reset itself.

SOURCE: We have a coleman electronic ignite propane

This furnace should have a diagnostic light that will give you a starting point where to look. It is located on the control board and will blink a code. If you remove the panel with the door switch on it, you will erase the code. Look for a small viewing port that looks on to the circuit board. Once you get the code, look on the wiring diagram for a explaination of the codes.

On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).