Armstrong Furnace

[Marion(57 Loboy)]

I got a vintage? Armstrong 32'000btu natural gas heater, that I'd like to use to heat my new workshop. Model Number 5551A-GS-40. It appears to be all there, and came with a two wire thermostat as well. Anyone here have experience with this brand/type heater? It's reported it was in working order when taken down from a walled off equipment maintainence area in a barn. I think I'll try and test it prior to spending any time hanging it in my workshop. The valves and such much resemble the stuff on the old Niagara Deluxe furnace in a home I used to own. It was a 150,000btu cast iron and heavy gage sheet steel behemoth, but it heated the 3 story home and basement like it was nobody's business. This Armstrong heater has a cast iron exchanger as well. I looked online for a bit, and found no results for a manual, or if Armstrong is even still in business. I'm hoping to get some help here with it. If it works, I'll be hanging it, fabbing a cold air inlet that will accept filters, and probably install a main trunk to spread the heat out. Or, is that just overkill?

[Jim Becker]

Armstrong is part of Lennox. I have an Armstrong in my workshop. If yours has a cast iron exchanger, I suspect it is really old. That may explain the lack of manuals or anything else online. If you are going to run it a lot, it may pay to get a new unit that is more efficient. New units today run from about 80% to 97% efficiency. An old one is going to be 80% or less. Does it have a data plate that gives both input and output BTUs? Divide them to get the efficiency they claimed when it was new.

What are the dimensions of your shop? If it isn't too big, you won't need much for ducting. In any case, you will want something to point the output down.

[Marion(57 Loboy)]

I'll only be heating 384 square feet, 16 x 24 x8' walls, and only when I'm out there.

[Jim Becker]

That much space won't need much ducting. I'd probably do a box on the furnace then one outlet pointing sort of near each end of the shop. Getting the cold air return to draw from near the floor is probably more critical for getting good performance.