EFM 350 Plans?

Hey stoker man, any plans to bring back the 350? The 520 is a fine unit, but really really big for most homes. Just wondering as you guys have brought back another model.

It's been discussed, but I don't know the status at this time.

I believe that it would be a good seller. Here's hoping!

Paulie wrote:I believe that it would be a good seller. Here's hoping!

Not Much different in size You will not save that much room The biggest differents between the two is water Capacity and smaller burning pot.
AP-520-1 40 gal in boiler
AP-350 30 gal in boiler
S - 20 stoker used in both .
Max Feed for a AP - 520-1 Early model 8 Teeth 20 lbs Per Hr. Smaller Burning Pot on the older 520
Max Feed for New DF - 520 - 10 Teeth 25 lbs Per Hr. bigger Pot
Max Feed for AP - 350 - 6 Teeth 15 lbs per Hr.

AP - 350 Dimensions

Boiler top 32 7/8" Long - 23 5/8" Wide - 27 3/4" Tall

Base 32 1/2 " Long - 24 1/8" Wide - 24 1/8" Tall

AP - 520 Dimemsion

Boiler top 36 7/8" Long - 25 1/4" Wide - 28 3/8" Tall

Base 36 1/2" Long - 26 1/8" Wide - 24 1/8" Tall

My EFM 350 said it has a S-15 not a S-20, I think the EFM 350 output is still better suited for the modern home. It is more of convenience for EFM to offer one model and say there is not much different. However the price difference to make has to be about the same. No big savings in materials.

EnergyManager wrote:My EFM 350 said it has a S-15 not a S-20, I think the EFM 350 output is still better suited for the modern home. It is more of convenience for EFM to offer one model and say there is not much different. However the price difference to make has to be about the same. No big savings in materials.

The S-15 Was Used On the early 350 by 1967 they used S-20 I see you have a 350 is it a Sq. Boiler Or a Round boiler
The S-15 was Also was used on the AF-150 Hot Air

I have a si5 and a s20 stoker setup sitting on the bench and the onlty differences I can see are the revolving arm on the gear box is stamped with the S15 and the burn ring is smaller. There is a thread posted by Chris that shows the old archive parts lists for a S15, S20 and S22. The blower castings are the same #'s and just about everything else is the same. Scott

I would not be surprised if the Kinematics of S15 revolving arm is different then the S20. Having two of them side by side what is the dimension centerline to centerline of the revolving arm. A smaller arm even slightly will give less linear travel. Consequently it would translate into bringing less # of coal up the tube an hour even if the everything else on stoker units is the same. https://en.wikipedia.org/wiki/Kinematics

When I measured center to center they were around a little more than a 1/4" if I remember right. It translates to 3 teeth on the travel. 1/4" this way and a 1/4" that way. 3 teeth.A better way to picture this would be two different circles, one three teeth smaller than the other. It only means that your adjuster on top will have to cover a different amount of teeth to set feed rate. On the older units the adjustment was on the revolving arm. By making the arm smaller or larger you could change the feed rate. Check out the archive thread, the parts are all the same. I know a guy with a 350 that has a full 10 teeth travel. The stoker in the 520 outside has 7 teeth of travel. The stoker units are the same, they just have different arms. I would think that the unit with the most heat absorbing surface would have the advantage of being able to pull more heat out of the same burner unit set at the same feed rate. But then again the unit with the smaller amount of water would have the return temp have a bigger influence on the overall operating temp. Which would mean faster heat transfer. I am just SOOOOO confused Scott

Good Job, this all shows us the the original Designer of the EFM stoker new alot about engineeering. It was well thought out.

I have a 350 that I'm in the process of restoring. I'm changing it out with the 520. I'm only running 4 teeth and really just don't need all that power. I'm going to be downsizing as soon as the kids all move out so smaller, more compact would work Scott

stokerscot wrote:I have a si5 and a s20 stoker setup sitting on the bench and the onlty differences I can see are the revolving arm on the gear box is stamped with the S15 and the burn ring is smaller. There is a thread posted by Chris that shows the old archive parts lists for a S15, S20 and S22. The blower castings are the same #'s and just about everything else is the same. Scott

First all the early S-15 & S-20 Stoker Had the feed rate Adjusted By the Arm. The Feed Adjustment up top did not come out until later mid 60S I know For A Facted That The Early S-15 And S-20 Had Smaller Pots goto That Pic that stoker man posted of the Smaller pot with the gooseneck on the bottom is a early one that was sent down there to show them at efm it was not there pot The Pot itself is smaller not just the Top Ring .I can show you at least 15 more of the early ones . They where alot of little & big Changes over the years with efm's. There is not enough room on this forum Explain them all One More thing to Remember The People that knew About all of the Changes over the years at EFM Are Long gone . I would Put money on it that know one there now Probably every seen a AP-350 either the Round Top boiler or The Square top boiler Or even a 700 900 1300 . Well I can think of one Person down there that might of seen
them. Bottom line is there where alot of changes from the time the company opened in 1922 to the Present .

Well,,,, all things being even,,,, I still am just as amazed as I was 2 December's ago when I saw My first coal burner of any kind. It was a 1960ish 520. I took one look at the burn pot crankin' and said to myself "this is the real deal" Since then it has become my most favorite thing. The way you know all about the EFM's makes me think they are your favorite thing too J.C. Keep the good info coming and be sure to include us when you find some more interesting coal burners. We are gonna have to get you a camera though, I keep hearing about these big beasties but don't ever get a chance to see one Keep warm Scott

stokerscot wrote:Well,,,, all things being even,,,, I still am just as amazed as I was 2 December's ago when I saw My first coal burner of any kind. It was a 1960ish 520. I took one look at the burn pot crankin' and said to myself "this is the real deal" Since then it has become my most favorite thing. The way you know all about the EFM's makes me think they are your favorite thing too J.C. Keep the good info coming and be sure to include us when you find some more interesting coal burners. We are gonna have to get you a camera though, I keep hearing about these big beasties but don't ever get a chance to see one Keep warm Scott

You will have to Take a ride down to the breaker's to see the big EFM's and the Losch'es
As for being My Favorite thing Yea one of many things My first efm memories are from my Parents first house
back in the 60's AP-350 Custom line cabinet door as well as Grandparents AP-520 My Aunts & Uncles AP-520 Both
Neighbors AP-350 & AP-520 Custom line cabinet door . Plus all of the ones I get to Move look at and Play with on the Weekends Lots of Older & Rare ones there All Differents Configurations .

I was hoping for a tour before a winter Meet & Greet. Would have been fun. Scott