Suburban furnace issue? Maybe not?

[X-Treme]

So, I've noticed recently (and maybe it's always been this way), that when my furnace comes on in my 2011 3500RE, the burner only runs for short periods of time. So, for instance, if my furnace comes on and runs for 5 minutes, the burner probably runs 3 or 4 times in that five minutes. If this was my house furnace, I would almost think that it has a dirty flame sensor. Is this normal? Not normal? Anything a handy guy could do, if it's not normal?

[X-Treme]

Crickets....

[Starmaster]

Ours in our former SOB did the same thing. How close to the thermostat do you have a heat register? If its too close, the hot air from the register can blow directly on the thermostat and make it think the whole trailer has warmed up, it then terminates the call for heat. At that point, the furnace blows for a few minutes to remove any residual heat in the firebox. While this is happening, the thermostat cools of enough to place another call for heat and fires the burner before the firebox cools off and the blower stops. As a result, you get the multiple firings while the blower continues to run until the trailer warms up to the temp set at the thermostat. Try redirecting any heat registers that are blowing towards the thermostat.

Another possibility is that there is restricted airflow and the burner is shutting down on high firebox temp. If this is the case, the thermostat will call for heat until satisfied and the burner will cycle as the firebox reaches overtemp and then cools off. Check to make sure there are not any obstructions in the furnace air intake and exhaust ducts.

Regardless of the reason, one option is to live with it, a little annoying and some increased wear on the blower. The other option of course is to find the reason and repair/resolve it. If the cause is the first possibility, not a big deal. If its because of the second, that's more of a safety issue and should really be resolved.

Good luck, hope the above helps

Dave