Keystoker or Harman Boiler

Greg,

I have the Alaska 140 Auger feed system, and it has jammed twice this year from a piece of oversized coal. I use Blaschak coal, and I called and spoke to Jack about the problem. Jack told me that they are installing screens on their bagging units to prevent this from happening in the future.


Mike

Hi Mike, my only experience with an auger is in my 'antique' 1930's IronFireman underfeed stoker.

I experimented with some large coal, just to see if it could jam. My auger crushed the pea and nut size pieces without jamming. The shear pin on my auger is a steel pin about the diameter of a pencil, I'm guessing 5/16" diameter. I'm pretty sure the belt-drive to the gearbox would slip before the shear pin would break.

I have had my carpet-bed stoker clog or jam with wet fines, and I've had it not work with buckwheat size coal. I just think the carpet type stokers with gravity feed hoppers onto the pusher-block are more prone to difficulties.

HOWEVER a very improtant point, you are an installer, with hands-on experience with many units, so your experience and opinions carry a lot more weight than mine.

I have an EFM stoker unit, not a boiler or stove, just the stoker. It is VERY heavy-duty, should last about forever. The bed type stokers I've looked at are made of fairly light-weight steel, except for the grate. The gearboxes are not all that impressive, you can jam and stall the pusher block and gearbox. Maybe it is all that is needed, but the extra heft in the EFM unit is very reassuring.

I think all the stoker designs will work for a very long time and last for decades given proper maintenance each spring and fall. The problem is proper maintenace often takes a second place to watching the game, eating dinner, etc, etc. The it is forgotten till next fall. Rust attacks the mechanisms that have moist acidic coal sitting on them all summer. YECH!! I'm sure you get service calls and see exactly what I'm talking about.

Greg L.

.

I looked at the EFM boiler web page, looks like an older design, but probably built like a tank. Its minimal firing rate is 2 1/2# per hour, which is higher than my house would need. The Harman stoker can fire down below 1# per hour, which will save coal during the warmer weather.

The Harman stoker is a fairly beefy design for a carpet bed stoker, a PSC motor, with needle bearings, driving a ball bearing roller into a steel yoke, that rides on heavy bronze bushings. I'm not saying it can't jam, but it seems stronger than other plate type stokers mechanisims.

Both the Harman and Keystoker units have very low flue outlets, also, the Keystoker has a double baffle design, the Harman, a single, but with 8 water tube going across the top of the firebox.

I hope to see a Harman in the next couple of weeks, I would love to compare it to the Keystoker, but don't know who in North Jersey deals for them. For the Keystoker, I would go with either the smallest unit, or the next one up. If anyone has pictures of the smaller Keystokers, it would be helpful.

Thanks again for all the replies.
Bill

Highlander wrote:I looked at the EFM boiler web page, looks like an older design, but probably built like a tank. Its minimal firing rate is 2 1/2# per hour, which is higher than my house would need. The Harman stoker can fire down below 1# per hour, which will save coal during the warmer weather.

In comparing coal boilers low firing rate is where the A-A and AHS boilers shine. The smallest size 130,000 BTU contains only 27 gallons of water, less than many other similar capacity boilers. The means less standby loss during low firing conditions. With optional ash temperature measurement system and a Honeywell indoor/outdoor temperature sensing aquastat you would have a very, very economical operating boiler. I would guess a A-A or AHS boiler with these controls would be well under 1 pound per hour coal usage.

Yanche

The minimum firing rate is for continous running, all boilers and furnaces have timers that run the stoker for maybe 2-3 minutes every 30 minutes just to keep the fire going when the thermostat is not calling for heat. If the thermostat and aquastat are in the circuit, they will shut off the feed when the water has reached the desired temperature.

In my antique stoker, I have three drive pulley selections for coal feed: 10#, 20# or 30# per hour. I use either the 10# or 20# pulley setup depending on the weather temperatures. The aquastat calls for heat to warm up the water, this current goes through a repeat-cycle timer. It is wired and adjusted so that it will run for 10-15 minutes then shut off the coal feed for 15-20 minutes. While the feed is shut off, there is a secondary combustion blower feeding air to the coal bed. So the auger-feed stacks up the coal, shuts off, the addtional fan burns it down, if the aquastat is not satisfied with the water temp yet, the repeat cycle timer starts over again. 10-15 on, 15-20 off.

So when I have the feed rate at 10# per hour, I use at most 5# per hour, or if on 20#/hr, use is at most 10#/hr. I can adjust the timer down to only a minute or two per hour if I want.

So the minimum setting of 2.5#/hour is only if there is no timer in the circuit and the aquastat is continously calling for more heat.

As for the boiler and heat exchanger design, the EFM has a low outlet too, I think they all are pretty effecient units. I think a phone call to EFM is in order to get more info.

I'd buy an EFM boiler in a heartbeat if one became available on eBay or Craigslist for a reasonable price.

Greg L.

.

Yanche wrote:In comparing coal boilers low firing rate is where the A-A and AHS boilers shine. The smallest size 130,000 BTU contains only 27 gallons of water, less than many other similar capacity boilers. The means less standby loss during low firing conditions. Yanche

The A-A 130M has a 22 gallon jacket.

Highlander, I am using a Keystoker K-6 and it gets the job done. It is a well built and simple stoker. I have not seen a Harman in person. I have not heard anything bad about them.
The Keystoker would have to be ordered with the ash and fire door opening on the side you want, the Harmans are convertible because the base is a separate unit.
Keystokers used to have a bad reputation for going out in the summer. The addition of the small fan and motor that constantly blow air under the grate is supposed to have solved this problem and the folks at Keystoker tell me it increased the efficiency.
Another thing to consider is the Keystoker can burn rice and /or buckwheat. Rice coal can be hard to get in the winter around here and I live in coal country, so you want to know what the situation is locally where you are.

The EFM is an excellent boiler and well made. They are only sold through there dealers. I just heard last week they are up to almost 7k for the new 520. Used and refurbished units are advertised for $2500 to $4500. Not cheap! The boilers are made of what looks to be 3/8 plate as compared to ¼ for most other boilers. They run on a timer during warm weather to maintain the fire. They specify a 2 minute run once every 60 minutes and they can hold a fire during a power outage for 8 hours or more. The fire can be maintained indefinitely if you are willing to turn the worm manually every hour.
Most EFM installations I have seen run the auger directly into the coal bin using a dog box where the auger enters the bin to facilitate the removal of the auger should you encounter a breakdown. Most people have a 5 ton coal bin so this means you don’t have to shovel coal around for several months. As the coal level drops you need only make sure that the auger has coal on top of it.

I think you will be happy with whatever you decide to get. They all work. A good drafting chimney is also a must no mater what brand or design stoker you get.

Hey bill E.F.M has been around for over 75 years that should say somthing there. 2.5 lbs will give you 21.470 B.T.U.H. 25 l.b.s 214.690 B.T.U.H. AS for dealers there are 3 in N.J. 13 in NY and over 75 in P.A. THEY build them 47.7 miles from my house so theres alot in service in this area some are going for over 45+ years . they know how to build a coal Boiler and oil as well . the 3 dealers are as follows BELVIDERE # IS 1908-475-4894 LAMBERTVILLE # 1609-397-0415 ASHBURY 1908-689-2948 GO TO http://www.efmheating.com for the rest of dealers . the alaska-140 has a opt. water coil. hot air jacket with air filter. AND YES I had lots of experiences with efm my parents had one and both sets of grandparents. uncles and aunts. and not including every other house in the neighborhood. I THINK it would be worth a call to them. good luck . P.S. the 520 weight is 1300 lbs.

Coming to an end of my fourth heating season with the Harman VF3000. I have not had any trouble with it since day one. I started burning this season in October and have burned alittle over 4 tons for my heating and domestic hot water. The unit will idle very well if there is a warm spell, like now, burning very little coal. It's easy to use and the feed mechinism is reliable.
No dealers had this unit when I was looking for a boiler 5 years ago. I called the Harman factory in Halifax Pa. and told them I was interested in a VF3000 but wanted to see one in person. They probably don't like to have customers at their plant because they only sell to dealers. But they told me I could come to the factory and see one which I did. They also heat their factory with 5 of these units.
I don't know what they sell for now but I paid $3,500.00.

I was given a price of $4300 from a central Pennsylvania dealer for the Harmon VF3000. That was in September 2006

The price on the Harman stoker is close to what a local dealer quoted me this weekend. They should have one in stock in a week or so, I plan to go look at it.

I emailed AHS asking them for specifics on the S130 including the ash thermocouple and belt drive options.

Kirk, with your VF3000, do you have a feel for how much coal it burns in the warmer weather? Has the hot water coil ever run cold, or can the unit easily keep up with the demand? What kind of flue temps do you see when its running?

Gaw, with your Keystoker, did you go through a dealer, or did you deal with Keystoker directly? I have emailed them in the past, but they seem to respond to phone calls more readily.

The KA6 is probably one size too big for me, but it has the same number of grates as the KA4. The KA4 is probably very similar to the VF3000 in its capacity. How low can your boiler fire in the warmer weather? Do you have any pix of your boiler, that would be helpful till I can see one in person.

Thanks again for all the replies, this forum is the best. Bill

In warm weather, it only fires once every 15 minutes for I think 2 minutes just to keep the fire going. I loaded the hopper (250#) last monday and I will have to load it today for the first time since then. It's been cold at night but warm enough in the day to require very little heat. So I can't tell you exactly how much it burns during the day but it's not very much. I've also been keeping the Harman at 140 degrees for most of the winter, all except during the really cold nights. It really saves alot of coal and heats my home just fine with the method I'm using. It will burn much more coal to keep it 180.
I don't have the domestic water coil in the Harman. My oil boiler has a domestic water coil and I pump from the Harman to the retrun side of my oil boiler. (oil boiler is turned off) All my zones and domestic water come off of the oil boiler.

Hi Bill , I have a brand new Keystoker Boiler (model KA-2) setting in my basement. After ordering about mid summer , it took about 3 months to get Before next heating season , I've got to install EVERYTHING. For now , it's just being stored. The good part about this is ; I can take all the pictures you would like. Posting them may be another story. I can get them on the computor. From there , ?????????????? I'll see what I can do.

Bill, I bought the Keystoker used from a private party. The Keystoker was not going to be my first choice. I looked at and was considering the AHS unit and also would have taken an EFM but when the Keystoker came up with the ability to drop a zero and the coma from the up front price tag some quick math told me I could buy a lot of coal with the savings. I bought a gauge for the boiler through a dealer and also bought a gasket directly from Keystoker. Their factory is about thirty miles from me so it is just as easy for me to stop in there for parts if need be. The folks at Keystoker were great to talk to me for quite some time on the phone to answer some questions about setting it up when I first installed it.

You have to use a lot of hot water to run out on the tankless coil water heaters. When you reach the low limit on your aquastat the circulator(s) will stop and all heat will be kept in the boiler until the low limit is satisfied. This should be true of all boilers.

I have no pix for now. My unit being an older unit is slightly different from the current models, mainly in that it lacks the second fan. The folks at Keystoker will sell me an adapter and fan and motor to upgrade it like the new ones. They tell me that it will use less coal in the summer. I have some more questions for them about that before I do it. For now it idles with a fairly small fire bed and the stoker runs a little less than one minute every 15.

Thanks to Scott, who spent a lot of time photographing and then trying to upload 5M of pictures on a dialup connection, I am posting pictures of his new KAA2 Keystoker boiler, as it came from the factory.