Furnace blowing cold air only

You could use some black tape to identify the wires.

Yes I agree Black is Neg. but on my trailer they used white.
Thanks for answer on battery setup. :)

Yes, that sounds correct. I do not like the use of white for identifying DC negative. Red for positive and black for negative can save much confusion.

Well after reading other posts and more info on Batteries I believe I have it figured out.
I was never charging the batteries fully.
With the batteries charged to 14.2 (on charger) the furnace fired right up.
So the batteries must be maintained and up to charge.

Having the problem solved that leaves me thinking if I have them hooked properly.
Should I go Trailer Red wire to Positive+ on 1 battery and the White - wire from Trailer to Neg post on other battery
Then tie the 2 POS together and the 2 NEGs together.
Does that sound right?

I had a similar problem with the forced air furnace in our truck camper ('06 Okanagan). The fan would run and the flame would come on occasionally but not for long. After a good deal of investigation and detective work, we narrowed it down to the limit switch.

This switch is another fail-safe like the sail switch, but it monitors the furnace internal temperature. If it thinks it's too hot in there, it prevents the flame from firing.

A local RV repair shop quoted $450 to fix it, including re & re the furnace, disassembly, replacing the limit switch (and the sail switch too, being as how they already had it apart), and shop supplies. I decided I could almost buy a new furnace for that, so decided to have a go at fixing it myself.

Making a short story long, managed find both the limit switch and sail switch through the panel on the side of the camper. Had to removed much of the circuitry, the fan and the shroud that it turns in. This gave access to the two switches.

Found them both on Amazon.ca for approx. $25 bucks each. Replaced them both, and the furnace has run well ever since (almost two years now). It was the limit switch that had failed -- on the bench with the ohm meter, the removed sail switch worked perfectly.

Good luck with it...!

RollandBC wrote:
Well it seems like it needs more Volts than the 10.5 it says it needs to ignite.
This morning at 11V it would not ignite.
So I'm charging it back up to 12.5 and we will see then I guess.

They might have been new this year but they're far from new now. You should be charging to 13.2V float (what you can measure while the battery is charging or freshly charged) and only drawing your batteries down to 12.2V (50% discharged). 11.9V is considered 100% discharged and getting down to 11V is definitely in permanent damage territory.

ok I will try again in the morning with full batteries and gas, I know the FAN will start.
I will listen for the clicks which I do not remember hearing during the last try.
But I have heard them on previous tries so I will see.

I have Owners Manual and all appliance manuals, including the Excalibur but not as detailed as the PDF above.

a manual for your furnace if you do not have one
Excalibur 8500 series

That is correct voltage AT sail switch

Then spark electorde should be firing (LOUD CLICK CLICK CLICK and gas valve opening

IF...circuit board is good and Batteries can maintain voltage.....which with them going down to 10.2 they might not be able to handle a load

ok rechecking and going +RED to white wire on Sail Switch and -BLK to YEL wire in white plug on board reads just over 12v