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tcrsolutions
11-14-2010, 11:10 AM
I have a '95 Scenic Cruiser Diesel Pusher. I noticed last winter that the propane furnace will not ignite on batteries. The blower motor comes on and works just fine, and you can hear the electric igniter try to light (3 times); but all that blows out is cold air. When the generator is on or plugged into shore power, it ignites and works just fine. I assumed it was just the battery voltage was low and that was causing the problem.

Well, we went out over the weekend and I had the same problem; so I decided to get some new batteries yesterday. I hooked them all up and they have an excellent charge and voltage. I attempted to see whether the furnace would work solely off the batteries today and I am having the same problem. Again, it ignites and works just fine when plugged into shore power or the generator is on. Is it possible it is a relay? If so, where is that located? Does anyone have any other suggestions or thoughts to this problem?

Thanks for any suggestions!

Chris

tcrsolutions
11-15-2010, 11:53 PM
OK, so I've done some troubleshooting. Still looking for some assistance here. This is what I've done:

Using a Multimeter, checked voltage at the batteries: 12.75 volt on a full charge. Check the voltage at the converter, 12.5 volts (already a loss of .25 volts on a 6 foot run with 2 gauge wire to the inverter).

Check the voltage at each of the fuse terminals on converter and reads 12.5 and check voltage on the hot lead at the furnace and it is also 12.5. Turn the thermostat on and before the fan kicks on, the voltage dips to 12.4. Once the blower motor kicks on, it dips to 10.5 then goes up to 10.9. You can hear the electric igniter clicking and you can see the spark, but nothing lights. After 3 attempts, it locks out and the blower stays running.

I had some extra 12-gauge electric wire, so I decided to run a direct run from the batteries to the furnace. I ran two ~25 foot wires through the window and hooked one up to the positive and one to the negative and connected the yellow ground wire to the negative and the red hot wire to the positive and checked the readings. The reading was 12.7 volts. Interesting enough, when the blower motor kicked on, the voltage only dropped to 12.1 volts and the electric igniter lit and everything worked great. The voltage actually seemed to climb a little the longer I let it run, which was also interesting.

So, I'm assuming I've got a bad ground or a bad wire somewhere. Since the problem occurred with the older converter and now the new converter, I'm less likely to think that is the problem. I would think I would have a lower reading when checking voltage at the furnace wire than at the converter if the wire/ground were bad, but not sure on this. I have yet to try running a direct run from the converter to the furnace. I'm just trying to figure out if I'm missing something completely obvious here. What about the .25 volt drop on 2 gauge wire on a short 6 foot run from the batteries to the converter?? All other appliances work just fine.

Any help or insight would be much appreciated!

GStream40
11-17-2010, 08:13 PM
Check all the wiring connections and connectors. Look for loose/corroded wire/connections. Also check all your ground/negative connections.

That is what it sounds like to me. The lower 10.5 voltage is not spinning your fan fast enough so that it triggers the "Sail Switch" in the furnace which turns on the gas for the furnace.

Ron

darbyjudy
11-18-2010, 09:08 PM
I had somewhat the same problem on my SunVoyager and the mechanic found the furnace setting on the wires that go to the furnace and they were partly worn through. He got rid of the excess wire and the problem was fixed.

Midniteoyl
11-22-2010, 11:34 AM
Check all the wiring connections and connectors. Look for loose/corroded wire/connections. Also check all your ground/negative connections.

That is what it sounds like to me. The lower 10.5 voltage is not spinning your fan fast enough so that it triggers the "Sail Switch" in the furnace which turns on the gas for the furnace.

Ron

Wow....