Suburban furnace supply line nut size?

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Not enough room to trouble shoot suburban furnace, I have to pull it out and work on it in my carport. I need to know what size the female supply line is so I can hook up propane to it. So I don't have to
Drag the thing to the store with me. Electric wires just going to extend, 15 feet.

Model is sf-30

Anybody know the size?

Thanks

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Thanks.

Appreciate it very much

[Chris_Bryant]

Yep, the furnace will have a 3/8" male flare on it.

[Old-Biscuit]

IIRC.....3/8"