Furnace name is International model 1125

[Lothlorian]

My trailer is a 1960 overlander and the furnace is a 1125 International. Made in St. Louis. Does anybody know anything about them?

It is the box with the white grill on the front.

Brian

[Inland RV Center, In]

Originally Posted by Lothlorian

My trailer is a 1960 overlander and the furnace is a 1125 International. Made in St. Louis. Does anybody know anything about them?

It is the box with the white grill on the front.

Brian

Brian.

DESTROY IT.

They are famous for exploding when you attempt to fire it up.

There were many recalls on it when it was in warranty.

Many new parts for them were discarded by everyone that had them, some 30 or more years ago.

Andy

[markdoane]

I'd say if it's 50 years old it's probably due for replacement. The International Oil Burner furnaces were prone to rusting out.

On top of that, the transformer required to run them on AC and DC weighed about 20 lbs. Replace with a Suburban NT or SF model.

[Lothlorian]

Mark:

Thanks for the info. I need to rip out the old and look at the duct work. I want air blowing through all the ducts.

Thanks again

Brian

[nmbosa]

Take lots of pics as you pull it apart and make sure you don't throw out any of the duct work until you decide what you are going to do and you have completed the install. Retrofitting a modern Suburban into that location is tricky when it comes to the duct work. I'm working on that right now on my trailer.

If you don't plan to camp in terribly cold weather, you might consider just disconnecting the furnace and leaving it in place.

Norm

[Lothlorian]

Thanks for the info. Please take pictures of how you fit your suburban . How many btu's is your suburban. I really do want to have a furnace.

Brian

[markdoane]

Brian,

I used the SF model, which is the low profile model. You might want to use the NT model which is closer to the form factor of the original International.

Mine is a 20k btu model, but all the different capacities are the same outside dimensions. 20k is fine for my '59 Tradewind, you would want to go larger for the Overlander. My furnace was mounted inside the kitchen base cabinet under the sinks.

The ductwork follows the general arrangement of the original, with outlets in the front, under the streetside bed, and the bathroom. The picture below shows the layout of the ductwork. There is also a springloaded trapdoor in the duct which directs heat to the graywater tank under the floor.

[Lothlorian]

Mark:

Now that looks good. I am going to have to investigate this because the old furnace has the air blowing towards the wall into the duct work. The white furnace door is a filter where the air comes in. I really won't know until I get the old one out.

You are saying I will need a 30,000 btu because mine is a 26'. It only has 23' living space. The old furnace does not look like it was that big. I bet the 1125 means it is 25,000 btu.

You know what I hate about buying a new trailer? I am at work wanting to get home to play with the new trailer. This is going to be fun.

Brian

[nmbosa]

Originally Posted by Lothlorian

Please take pictures of how you fit your suburban .
Brian

Will do. I'm hoping to get back to that part of my rebuild this weekend.

Originally Posted by Lothlorian

How many btu's is your suburban. I really do want to have a furnace.

I bought the Suburban NT30. I didn't think the 16k btu version would be sufficient. I'm pretty sure the NT30 will be too much, but I'd rather have too much heat than not enough.

I felt the same way you do about the furnace. I figure if I'm in an RV, I should be warm and cozy, not freezing my a.. off like I was in a tent. It gets cold up here in the PNW.

Mark's photo's of his duct work are very helpful. My set up will be a lot like what he has done, but probably won't look so professional.

@Mark, could you post up a photo of how the two round ducts join the rectangle duct work?

Norm

[markdoane]

Here is a picture of the round-to-rectangular transition. The second picture (furnace removed) shows how the rear round duct feeds a tee that curves back under the furnace to feed the front discharge.

[Lothlorian]

Mark:

You have done a great job. I am saving this thread. First I will start gutting. Did you take your belly pan off when you started working on your trailer? Was that a challenge? How did you get it back on.

Brian

[markdoane]

The belly pan came off fairly easily. I drilled out the rivets then slid it back over the axle and out the back. It was fairly dented up and rust stained.

I ended up replacing it all with new aluminum.

[nmbosa]

Mark, nice looking work. Thanks for the pics. Did you build the rectangle duct lines yourself?

Brian, this is a good thread. I'll post up pics of my install when I get there. My plan is to place the furnace directly on the floor and run two of the 4" round ducts towards the rear with an outlet just before the bulkhead between the kitchen and bed area and a second outlet toward the rear of the bed area (can't go any further cause the bathtub is immediately aft of the bed). We'll see if I can work that out as there is not much room in the kitchen cabinet for all the ductwork. It's probably going to require a bit of custom duct work.
Norm

[Lothlorian]

This is a good thread. I am going to start gutting tomorrow after work. I have lots to do. Any threads you have with your renovations link me to them.

Brian