Furnace ignitor & battery

[JAB]

Hi All,
The furnace in my CT 13 is not working (it had been running fine). This may be a dumb question: does the battery provide the ignitor with the "spark" it needs? So if my battery is dead, the furnace won't start even though all other systems (gas, thermostat, etc) may be OK? My manual under "Furnace Troubleshooting" doesn't mention anything about the battery. It does mention "low voltage" and I assume the voltage comes from the battery; why don't they tell you to check your battery (and charge it) if that could be the problem? I'm charging the battery now but I thought I'd ask the forum for more understanding.
Thanks in advance - you all are always helpful.
John

[ZachO]

It absolutely will not work without a well charged battery. What happens with propane heaters is that first, the furnace circuit board (powered by the battery) kicks on the fan. IF the fan gets up to the right speed, which is completely dependent on the battery having enough power to get it up to full speed, it will ignite the burner. If the fan doesn't get spinning fast enough, it will not spark and will turn off the fan and shut down.

Thermostat tells the circuit board to click on; power goes to fan; fan gets up to a speed fast enough to blow the sail switch closed; which tells the ignitor to spark.

More or less.

[JAB]

Thanks, ZachO, very helpful. I have the battery charging now. I read it takes a few days for a full charge. JAB

[mary and bob]

The furnace in our CT was voltage sensitive, worked OK on shore power but erratic on battery. Removed the furnace and made the space into a storage drawer.

[JAB]

I charged the battery (for about 24 hrs) and just tried the furnace - it works! So I had a "duh" moment by not thinking the low battery was the problem right away - always try the easiest solution first. And I'll have to charge the battery more often during the summer.
Thanks for your help.
John

[ZachO]

It's a learning process! Most times when I tell people what appliances I have, they assume the furnace just runs on propane. In reality, the furnace is the largest draw on the battery of anything in my trailer.

[JAB]

Come to think of it, the blower on the furnace would be running off the battery also. I'll have to be aware of that.
Thanks again for your help - I printed your responses for my folder.
Johns

[ZachO]

Exactly. Blower = fan. It's a safety feature. Without the blower, the furnace would overheat. So unless the fan/blower hits the right speed, it won't allow the furnace to ignite.

If your furnace blower/fan comes on, but you never hear the flame ignite, and after a minute or two the furnace turns back off without ever putting out any heat, that's most likely what's happening. Fan/blower speed never hit critical mass, so it all shuts down. This could mean a low battery, but could also mean a failing sail switch. Both are things that do happen if you own the trailer long enough.

[Raspy]

JAB,

It's not a good idea to just charge the battery when it's dead, or just once in a while when you think of it.

Allowing the battery to repeatedly get below a 50% charge will ruin it.

You need a battery tender, or a smart charger that you can leave connected all the time. Then the trailer will be ready to go and your battery will remain in good condition for a long time.

[JAB]

ZachO, Thanks again... I understand the system better.
Raspy, I'll take your suggestion. I'm wondering if I can leave it plugged in to an AC circuit - would that be too much? Perhaps plug it in once a week for a day so it never gets too low?
John

[Raspy]

Originally Posted by JAB

ZachO, Thanks again... I understand the system better.
Raspy, I'll take your suggestion. I'm wondering if I can leave it plugged in to an AC circuit - would that be too much? Perhaps plug it in once a week for a day so it never gets too low?
John

You should be able to leave it plugged in all the time. I don't know what converter/charger you have. A smart charging regimen is what works best for the batteries and you might have to buy a new battery tender, to get the best results, if yours is a constant voltage converter.

The correct charger/ tender would have a float voltage, for conventional flooded batteries, of about 13.2 volts. Leave your trailer plugged in a for a day, with no load on the battery, and read the battery voltage. A cheap digital, cigarette lighter volt meter, available on Amazon for about $6. is perfect for this.

Sorry I can't be more specific. Maybe someone else will chime in.

[mary and bob]

The original power converter in the Uhauls was not a smart charger. Probably was no cigarette lighter plug either although ours has one but may have been added by a previous owner. The original power converter is an orange color box in the right rear compartment and is outdated technology by todays standards. No telling what may be in the OP's trailer without more information or photo.

[kim_w]

Thank you for posting this question. I was about to ask about how to get our furnace working in our C13. We've replaced every part. Next time, I'll ensure that the battery is charged and hope that's the fix!

JAB - where did you get your manual?

[mary and bob]

[QUOTE=kim_

JAB - where did you get your manual?[/QUOTE]

Repair manual, operators manual, and parts manual are all in the document center. To get there click on "more" at the top of the home page, then on "document center", then go to bottom of the page where trailer brands are listed and click on Uhaul. there is some other info there too.

[Doctor Harold]

I have a Battery Tender brand charger that works well and can be left on 24/7. I once left the Scamp plugged in and let the power converter keep the battery charged -- bad idea. It boiled the battery badly. Newer and better converters may be okay to leave charging, and I'll be researching that when I replace my converter and battery in the near future.

Stay away from the cheap float chargers sold by Harbor Freight. My son bought one and it ruined a brand new battery. You get what you pay for.

Harold

[Glenn Baglo]

Well, your converter is apparently 44 years old, if original, so I wouldn't expect the latest technology.

[Doctor Harold]

Originally Posted by Glenn Baglo

Well, your converter is apparently 44 years old, if original, so I wouldn't expect the latest technology.

I have no idea how old the converter is. I was told that it had been recently replaced when I bought the Scamp about 2 years ago. Of course, recent means different things to different people. I'll have to pull it out and see if there is a date code on it somewhere, but I doubt it's original -- or fairly new.

One thing for sure is that it's getting replaced before my next camping trip. New or old, it's not trustworthy.

Harold

[toothless25]

I have a working original for make an offer, the shipping will be whatever the cost

Vhttps://www.fiberglassclassifieds.com/u-haul-ct-13-power-converter-343

worked great, I replaced mine with 500.00 magnum

Dave L

[JAB]

Originally Posted by kim_w

Thank you for posting this question. I was about to ask about how to get our furnace working in our C13. We've replaced every part. Next time, I'll ensure that the battery is charged and hope that's the fix!

JAB - where did you get your manual?

Hi Kim,
Sorry for the delay.... we were off the net for almost 3 weeks.
Our manual was with the CT-13 when we bought it used. It's the UHaul maintenance requirements and pretty thorough although they didn't mention a dead battery causing the furnace to not start. Were you able to download one with Mary and Bob's instructions? John