no heat

[frosty]

My furnace in our 1998 fifth wheel (new to us) was lighting sporadically, and now not at all.  The fan goes on, and I can hear some snapping (ignitor?), but no heat. 

The propane is on, and tanks full.  I can smell propane near the furnace outside vent, so I know it is getting gas. 

Any ideas?  I have a service contract.  Should I call this in?

Frosty

 

[cuts_up]

Are you just checking out your heat to get ready for winter?  Or do you really need to use a heater right now?  Just curious. 

 

[Woody]

The snapping you hear is the ignitor trying to light the burner, either your control valve is bad (rare) or something like a spider web is blocking the burner tube or orifice (common). A couple of months ago my hot water heater was burning with an orange flame and smoking badly and after taking it apart I found that just a couple of strands of spider web was enough to effect the flame.

Woody

 

[John From Detroit]

As the previous poster mentioned spiders.. There is a spider that just loves the smell of natural gas and/or propane so tends to build it's nest in gas jets.  Step one is "Standard preventive maintenance procedure one" that is, the routine maintenance outlined in your owner's manual.

If you don't have an owner's manual try download from the furnace maker's web site

if that fails try "The RV BOOK" or "The RV Owner's Handbook"

Both have "Generic" instructions which cover the vast majority of units out there

And if that fails... Well,, There is always professional help (RV-HEVAC technician)

 

[frosty]

Just curious.  If there was a spider in the gas jet, would it  not get burned away the few times the unit actually fired?  I'm calling the RV repair.

Thanks anyway!

 

[John From Detroit]

No, because the fire is a long way from the jet.  The jet is at the start of a tube, there are at least 2 holes in this tube as well, as the gas comes out of the jet VENTURI principle sucks in air, the gas/air mixture then travels down the tube (mixing well in the process) and exits the burner where it then burns.  The spider builds it's nest it the jet (or in the tube)  Yes, some of them do build in the burner.. They get quick fried. but it's the ones "up stream" that cause the problems.