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turbojimmy's avatar
turbojimmy
Explorer
Dec 24, 2013

Converter and Furnace Questions

Hi all - first post here.

Just got an '84 Allegro. Not sure what it is - NADA doesn't show a 31 footer but my insurance company does. The model number on the tag under the dash stars with M31 so I'm thinking that's what it is. It has a bedroom with twin beds in the back which I have not seen before. It popped up on Craigslist for about the price of the tow to my house so I couldn't turn it down. The 454 in it needs rebuilt or replaced, which is no big deal for me (yes, I know it needs to come out the driver's door).

It had been sitting for 5 years. It was properly winterized and *almost* everything seems to work. With the engine being the #1 priority, there are a couple of other things that would be nice to remedy while I'm inside working on the engine.

First, lights are pretty dim. The more I turn on, the dimmer they get. When the furnace blower turns on, the lights noticeably flicker. Now, all 3 batteries are beyond gone. None hold any sort of charge. I'm wondering if the dead batteries have anything to do with the apparent struggle the converter is having? The 6.5kw generator won't turn over either (though I was told it works) - clicks like when you have a low battery.

Second, the motorhome has 2 furnaces. A Suburban NT-30 in the front and something smaller in the rear (Suburban as well, but can't find a model number). Front furnace works great and it's pretty apparent that the rear furnace is necessary to keep the back bedroom warm. It doesn't work. Fan runs, I have gas to it. It doesn't try to fire. No clunk from the gas solenoid; no click from the ignitor. Where do you begin troubleshooting? There's a lot of info on the web, but I'm not sure what pertains to something of 1984 vintage.

Beyond that, the thing was nicely maintained and is nicely appointed. I look forward to firing up a fresh 454 and getting on the road with it.

Thanks in advance for any advice!

26 Replies

  • Plan on replacing that converter.......it was not designed to run and supply the 12v DC system without batteries (good ones). that era of converter needs good batteries. The batteries supply the 12V DC system and the converter maintains their charge.

    Running it with shot batteries will overtax it......sooner than later.
  • No idea how old the batteries are. I know the rig has been sitting since 2008 when it was towed to a yard when the engine failed. It was towed a couple of other places since then, but apparently never put to use during that time.

    Batteries have to be well past their prime at this point. I'm going to take one out of my limo (another hobby of mine) to power the chassis. The coach batteries will have to wait for now.

    I told my brother that it's slowly waking up. After 5 years (possibly more) of sitting the systems are starting to come online. It's been plugged into my house for 48 hours now.

    I've been sitting in it out in my driveway for hours now to make sure both furnaces are cycling as they should be. They are. The rear one has decided that it's happy with the air flow now.

    Temps are dropping quick here in the Northeast. I'm going to let the furnaces run to see how they do.

    Thanks all for the replies. I will have tons of questions about this thing. My main objective is to get it mobile for tailgating and other nearby events. If I can get it to a point where it's reliable I may venture further......
  • If it's the converter I think it is, it charges at 3 amps max and always has to have batteries connected to keep the 12V clean.
    Any idea how old the batts are? If the sides are bulging then they're sulfated and past their prime.


    Scott
  • Better start with all new good batteries. Bad batteries can cause a variety of symptoms.
    The furnaces need good air flow for the igniter to fire. Batteries again.
  • ScottG wrote:
    The converter in something of that era is really a pretty poor performer. You'd be much better off with a new 3 stage unit and your going to need new batteries anyway so.. ;)


    Thanks! It does not appear as if this one charges the engine battery either. It just does the coach batteries. Seems like an opportunity to fix that, too.

    Not sure if it's the batteries coming back up a bit or not, but tonight things are much brighter. But not where I'd like it to be. The dark paneling of the day sucks up a lot of light, but I'm thinking maybe LEDs that draw less juice and are a bit brighter might do the trick Dunno.

    I got the rear furnace to fire. I removed the cover from the front and it fired. I replaced the cover, it got up to temp, but wouldn't fire again until I removed the cover. Air flow problem I guess. I'll have to mess with it. There is a sizable hornet's nest in the intake outside. I've read that they're pretty sensitive so I'll clear that out. It's a smallish furnace with just 2 outlets. If I could tap in another it might do it, too.
  • The converter in something of that era is really a pretty poor performer. You'd be much better off with a new 3 stage unit and your going to need new batteries anyway so.. ;)