Furnace power draw

nstate wrote:
Seems my propane furnace draws about 8amps while blowing. Doesn't seem like much but on/off throughout the night adds up. Are there any options regarding more efficient blower,mods,etc. Mines a single speed which is just high. Thanks

What kind of furnace do you have?

I just checked my Suburban furnace (16 or 20 K don't remember which). It pulls 1.6 amps when the blower first turns on and then 1.8 amps when the burner lights.

We have a low temperature thermostat, it goes down to 35 degrees. It really cuts down on the cycling and keeps the tanks warm enough not to freeze. We can live with it quite well, not all people can.

Good luck.

joerg68 wrote:

the air moving across the heater transfer system keeps the temp of the burner from not getting far more dangerous for fire potential

I would like to strongly emphasize that. The burner is designed to deliver a certain amount of heat that has to go somewhere. If the blower doesn't transport it away, it will stay there and heat up the furnace. I would not want to find out at what point it ignites the particle board wall of the neighboring cabinet.

But even if that was not the case... A slower fan will take longer to distribute the same amount of heat inside the camper. It might consume less amps when running, but it will run for a longer time. I would assume the fan is already designed by the manufacturer's engineers to work pretty well, so any gain would probably be small.

Two safety features designed into furnace
Sail switch-------closes when adequate air flow for combustion and heat dissipation is achieved
Limit switch------opens on high temp is sensed (typically 180*/190*F)

Low air flow..sail switch opens
High temp in heat exchanger...limit switch opens
Either one causes DC power to be interrupted to circuit board shutting down main flame/ignition

So you can see that you really can't circumvent this except by having the fan run less...and the only safe way to do this is to insulate. Either the camper...complicated, or yourself....pretty easy. Or just add a battery or two and some more solar and forget it.

Install a WAVE 3 heater, they work just fine.

To stop the cycling throughout the night, may want to consider add a blanket and just turn it on first thing in the morning.

the air moving across the heater transfer system keeps the temp of the burner from not getting far more dangerous for fire potential

I would like to strongly emphasize that. The burner is designed to deliver a certain amount of heat that has to go somewhere. If the blower doesn't transport it away, it will stay there and heat up the furnace. I would not want to find out at what point it ignites the particle board wall of the neighboring cabinet.

But even if that was not the case... A slower fan will take longer to distribute the same amount of heat inside the camper. It might consume less amps when running, but it will run for a longer time. I would assume the fan is already designed by the manufacturer's engineers to work pretty well, so any gain would probably be small.

I think OLD BIS is really right on this subject...the air moving across the heater transfer system keeps the temp of the burner from not getting far more dangerous for fire potential, so I would NOT slow that main fan down on the heating system. I have had the heater run alot during a very cold trip with just two 12v batteries and yes the draw took the batteries down, but not low enough that the genset would not start.

I found that I had an air flow issue. I found some ducts a bit too long for the run, so I trimmed them to stretch them out. I found the flow to be very low to the furthest points in the TC so I installed an inline blower and some extra duct to supply the back of the TC...I switched this extra fan so I can control the draw during the night when I am asleep and don't need the bathroom warm. But actual use has shown it is always on and I have had very little battery issues even when very cold. So when I add two more batteries, I feel confident that I will be just fine. My system keeps the TC comfy.

Any way to add an additional duct & vent to increase warm air flow?

I just added one on my trailer and may go one more. I am actually having issues with restricted air flow but still I think it will heat more efficiently with the additional ducting.

Interesting Skipro, thanks.

Already have two 6v golf carts, 150watts of solar,generator, every light converted to LEDS,and Wave3. Just trying to slash the 8w draw. Thanks guys