Atwood furnace

[cronin]

In Island Pond Vt couple miles from Canadian Border and temp is 32 degrees now Friday
Furnace went on great worked for 5-6 minutes and then stoped and just the blower keeps going on and off will not ignite
Any ideas?
Thanks Tim

[Persistent]

RV propane furnaces typically have a preprogrammed cycle.
1) Wall thermostat turns "on".
2) Fan starts and runs for a period of time to clear burner chamber.
3) Sail switch connects when proper air flow is detected.
4) Gas valve opens and igniter starts snapping
5) If burner lights, gas stays on until wall thermostat turns "off".
If burner does not light, gas goes "off" and fan continues to run. It will try to light three times then lock out.

6) When wall thermostat goes "off", gas valve closes but fan continues to run for a while to cool furnace.

Observe your furnace behavior. It can fail at any of these places.

Sometimes the thermocouple that detects the burner heat fails. Gas valve closes but fan continues to run for a while.

[stinger608]

I'm experiencing the same symptoms. Not sure what year and model your RV is, but take a look at this thread:

https://www.irv2.com/forums/f54/dome...es-612590.html

As you will see, I've pulled and bench tested the furnace outside the trailer, replaced the sail switch, and tried a new thermostat.

It would appear that the control module in the AC may be bad.

If you have a newer RV and are running the Atwood/Dometic furnace and AC it may be the control module.

Climb up on the roof and pull the cover off the AC and ensure that no "critters" have chewed through any wires also.

[Jkwilson1989]

Whenever an igniter-equipped gas appliance fails to ignite, you should remove power from the appliance, wait a few minutes, then reconnect power. The easy way to do this with the furnace is to pull the fuse.

The reason for doing so is that after several ignition attempts, usually three, the appliance quits trying to ignite to avoid constant igniter clicking. Removing power resets the controller allowing it to attempt ignition again.

[Old-Biscuit]

Once Flame is ignited the circuit board is waiting to detect the Flame Proving Signal generated by the flame.....it is a milliamp current that must be detected within 6-7 seconds of flame ignition

Spark Electrode provides High Voltage Spark for ignition
It is ALSO the return path for that Milliamp current for Flame Proving

Furnace starts, fan runs, gas valve/spark ignition......flame proving
3 attempt then lockout
Reset t-stat----repeat

Spark Electrode.......
Must be engulfed in flame
Electrode must be clean of soot/carbon (emery cloth)
High voltage wire connection on transformer/circuit board must be clean/tight
High voltage wire can not be loose inside the ceramic insulator
Ceramic Insulator can not be cracked
Spark Electrode Assembly ....mounting screw needs to be clean/tight (ground source)

If Spark Electrode is good.....then circuit board is issue