Simplex Multitherm

Does any one have, or used a Multitherm with coal. I need to know what size works best and any other info you can give me.

Hi, I have a simplex multi therm also. It was my grandfathers it was hooked up to the house when I bought it. It is currently disconnected and I will put it back in use soon. I remember when I was a kid my grandfather used it often in the winter. He burned coal in it. He used chestnut (nut) size coal. This unit will put out the btu to heat your house. This boiler was made to burn coal.

Hey show me some pictures when you get a chance. I would like to hear from you so I can ask you questions when I need help. I have not seen many of these units around. So if you have any input on parts or service fill me in. Thanks

Hi,

I have a Simplex Multitherm made by Van Wert in PA and I was told I can use wood with it. Can anyone tell whether this is true and if yes, how can I proceed to start using the furnace with wood? I'm attaching a couple of pictures.
Thanks in advance for any help.

Yes, I have one (and it is sitting idle in the garage ever since I bought the Keystoker Kaa-2). However, I used it for many years and have plenty of experience with it. By the photo you posted, I would guess our units are identical. My unit also has a oil gun port below the exhaust breech.

What can I tell you about it?

Most importantly, this is a solid unit. You have a good boiler there (which I myself did not fully appreciate for the first few years that I owned my home).

1. Don't waste your money burning oil in this unit. Testing will show you that, as an oil burner, you ought to scrap it. It's just not worth it; there are far better units. A new unit will pay for itself in less than 1 year given the 30% better efficiency you'll enjoy in a 2000sq ft home.

2. Yes, it burns wood. Effectively. And I did it right here in mid-winter in CNY. But here's the thing: you better have a lot of wood and you should either work-from-home or have a job that has you (or someone else) home every 6-8 hours because that's how often you'll need to load it. Sure, you can load it up to the rafters before bed and snuggle in for long overnight slumber and still have some burning embers in the morning. But the temperature will have fallen pretty significantly and the Samson thermostatically-controlled damper will be wide open. Wide open enough that it will be actively drafting tons of air through the unit and further cooling it. So, in the am you can wake up and easily get it going again. But don't think that you can then grab your coffee and climb in the truck and go to work. Nope. Not a good idea. The fire will restart, for sure. But because it is a high mass boiler with 1000# of steel and 320# of water, that fire is going to be BLAZING for quite some time before that damper begins to close around the thermostatic setting. I have seriously over-fired this unit to the point that the chimney pipe changed color and became brittle, ruined. If the boiler is near the target temp when you reload it, sure, you can go right on your way. But not if it is cooled down significantly. So, if you choose to use wood, plan on being married to it.

3. Coal is an entirely different story: it burned either stove of nut exceptionally well. With around 75-100# in it, it would easily burn all day without the above problems. Yes, you gotta shovel it in and shake it down 1-2 times a day, and, yes, it will waste more coal than any modern stoker. But not enough to meaningfully justify the additional cost of new stoker.

Here's a few more tidbits:

a) Use the unit only when it is cold, regardless of whether you use wood or coal. This bad boy will easily put out 140K BTU. But to keep even a small fire burning through a deep bed, you need draft. And you only get draft from chimney height, diameter, and temperature differential. You usually don't adjust the first 2 but weather changes the differential. And that little fire can get really smoldery and smokey on those warmer fall and spring days. It looks like an outdoor wood boiler. And you'll definitely need a "dump zone" to dump excess heat, especially on those warm days. The windows will be open and the inside of the house will over 80F. It will be perfection, however, during the cold months.

b) The Samson thermostatic draft controller will keep that high mass boiler pegged pretty close to target. Mine was just that good. But, you MUST make adjustments if you want to switch between wood and coal. I advise that you optimize for one or the other; don't try to switch back and forth.

c) Similarly: if you go with coal, use a baro draft regulator. If wood, I would avoid it. My concern is that creosote in this boiler is a BIG problem. Huge. All those hot volatile creosote gases directly condensing on the unlined steel smoke paths (which are water cooled 1/4" away) really does happen. I never had a chimney fire, but if I had, I'm sure the baro damper would have swung wide open and feed it like crazy.

If you have more questions feel free to ask!

Best of luck!

Thank you all for the replies and sorry for not replying sooner.
Well, I live in the country and have access to a lot of free wood, so much that I bought a 22 ton splitter. I get up very early in the morning to go to work and my wife works from home so loading the furnace isn't too much of an issue. We already have an insert in the house upstairs which works well for Fall and Spring but is not sufficient during the very cold days of January and February.
What I'd like to know is how to get it going with wood? Do I need to start it with oil and switch to wood? If so how? Shall I just start burning the wood but how will the pump start? Right now the furnace is turned OFF at the main. If I turn it back on it fires (oil) right away. Obviously I don't want that for wood. So what shall I do?
Thank you in advance

there should be a switch for oil/wood/auto. In oil mode the oil will only fire, in wood mode the oil will not fire, in auto mode when the boiler temp. drops lower than your settings, the oil will fire and heat the boiler. If someone is home all day keep it in wood mode,that way when your boiler temps. drop the oil won't fire and save the oil for when your not at home. Dennis


EDIT: i thought it was a wood burner also, but the same principal with coal. Dennis

Ok. So far I haven't been able to locate a switch with Wood/Oil/Auto functions. There is however a contact on the wood/coal trap door (see pic1) which is connected to a switch (see pic2 and pic3). On this switch is handwritten from top to bottom:
BOILER ONLY
ON
OFF
NOT CIRCULATOR (I think, that line is faded and is difficult to read)

When I turn the switch on the OFF position, the pump stops.
When I keep the switch on the ON position and open the wood/coal feeding door the pump stops also.

Should I keep this switch OFF and start feeding wood?
Thanks.

fguignard,
when you mean the pump stops when you open the door,does the oil burner stop,if so it's a safty switch so flames and fumes don't come out the door while the oil burner is on.My boiler is more modern and your boiler might not have all the new switchs on as mine.Try to Pm member kenbod since he has/had almost the same boiler as you for start up procdures and ask him for proper burning methods also. Dennis

i have a simplex multitherm to i just bought the house it burns real nice i just think im loosing alot of heat up the chimney i only have a damper on the flue with a knob what does anyone recommend?

If you only burn coal, I think you would be better off with a barometric draft control. If you burn wood even once in a while, you would need to cover the baro to prevent excessive cooling of the flue gasses.