Which Stove, the AHS Coal Gun or the Axeman?

Wonderful forum! I have gained much in reading many threads thus far. Thank you very much.

My question is for those who have an extensive knowledge of the Coal Gun and the Axeman coal boilers. Which one is better? The price is about the same when comparing apples to apples... both units are very similar in design. What are the advantages of one over the other?

Hello pret welcome to the forum well both are outstanding the A.H.S. is a hooper feed and the AXEMAN is a auger feed which means you can feed right out of the coal bin or a 55 gal drum so one you will have to keep hopper filled and one you keep coal bin filled hear are they site you might want to look at E.F.M another outstading unit also a auger feed they been around for over 75 years. so go and check them out you will be able to compare all three hope this helps you out

http://www.alternateheatingsystems.com
http://www.axeman-anderson.com
http://www.efmheating.com

I'm a happy AHS owner so I'll try to make this a unbiased as I can. We, collectively don't know much about the A-A boiler details. The information posted on the A-A web site is old. Current printed literature from them is just modern printing of old originals. Still shows a house wife in 1950's dress! The literature and the few, very few individuals that own or have owned I've talked to describe the unit as described in the available literature. BUT if they are still made that way, I would not recommend it over a AHS unit. The A-A unit has a single drive motor for the auger, combustion blower and ash grate. It's a kludge not something you would design today. The AHS has separate a direct drive combustion blower motor and a second gear drive motor for the ash grate. The A-A uses helical flighting in a pipe to convey coal. It's different from a screw auger. It runs continuously. Jeff at AHS says it noisy because the unused coal just tumbles back down the pipe. He also says it makes coal fines. Not hard to imagine. I don't really know. The AHS boiler was designed by Eshland. Jeff worked for them as a field service tech and installer. When the company closed Jeff acquired the manufacturing rights. The AHS boiler has no auger, just a hopper on top you need to fill, usually manually. You could auger or belt feed coal to fill it but you are on your own for design and implementation. Eshland did have helical flighting coal feed just like the A-A. AHS will sell you one, but they don't recommend it. They suggest a screw auger with home brew sensors that turn it off when the hopper is full. Both have domestic hot water coils available. A-A uses a flat plate seal type. AHS uses a 4" pipe thread seal type. I believe the pipe thread type is less prone to leaks. Both designs have the flue gases making a 180 degree turn inside the boiler. The hot spot in the boiler is likely at this point. AHS has a ceramic heat shield at this point. A-A has a steel plate. I've had NEPA plumbers who refurbish used coal boilers ask me if the AHS ceramic would fit a A-A boiler. That implies there may be a weak point there. I don't really know, I've never seen a A-A boiler. The A-A is a ASME certified design product. AHS is normally not, but is available for extra cost. Search the AHS web site for what ASME design means. I don't think it's important. The AHS unit is available with a modern Fuji contoller ash grate temperature proble. This is an important option if you want to burn through the summer. I don't have one, but want one. I'm waiting for the right price on Ebay. The A-A literature says they have a "heat sensitive switch". That's all I know about it. Hope all this helps.

If at all possible go visit the factory and look for yourself. My guess is that AHS is selling more "coal guns" than A-A is selling "anthratubes"

A few years back I looked into both of these boilers. In the end I didn’t end up with one but it has nothing to do with their quality or anything like that. For reasons mentioned by Yanche above I like the AHS and another reason I would have probably taken an AHS over the Axeman had I bought one is AHS will sell direct and Axeman-Anderson will not. If you want to save a few bucks and install it yourself you still have to pay a middle man to get the Axeman-Anderson. That’s OK as long as you’re the middle man.

gaw wrote:A few years back I looked into both of these boilers. ... another reason I would have probably taken an AHS over the Axeman had I bought one is AHS will sell direct and Axeman-Anderson will not.

I just went through the process of comparing the AHS and AA boilers and ended up buying the AHS. GAW is correct that AA's distribution is through installing plumbers/dealers---normally. In my case they were not able to identify a contractor serving my area and indicated that they would sell direct.

At quoted "regular" prices I think AHS and AA are comparably priced when feature adjusted. However, as has been noted in another area of this forum AHS has been running a "special" and offering a $1000 discount.

However, as described by Yanche there are some distinct differences--AA has the auger feed system as a standard component while AHS uses hopper feed as the standard component. An auger can be added to the AHS but it is not an option to remove the auger from the AA. My understanding is that AA uses a bimetal heat sensing unit to control the grate--no options--while AHS uses a timer as standard equipment and offers an electronic controller and thermocouple sensor as an option to control the grate. AHS offers a direct drive combustion blower as standard and offers a belt drive system as optional equipment to deal with the problem of regular (estimated to be 3-5 years by AHS) blower motor bearing replacement due to heat degradation. AA has standard a belt drive system--but it is much more complex because it drives not just the blower but also the auger feed and the grate. I understand that it also includes a number of electro mechanical components to change speeds for the auger and grate (because there is a single motor drive) and to cycle the drive (for the grate).

Because the AA has a fixed auger system there is a fixed relationship between the coal supply and the boiler that is not required with the AHS hopper--with the hopper and manual loading there is no fixed relationship between the coal storage and the boiler and even if using an auger with the AHS there can be a fair amount of flexibility because augers are available in a number of lengths and the geometry is flexible in both direction from the hopper and angle of rise to the hopper. With the AA all of these elements are fixed.

Thanks for your expertise in the matter gentleman. I am very grateful for your time and oppinion.

I will be purchasing an AHS this summer for a new construction. I will continue to read a ton in the coming months and hope to be able to contribute in the future. AWESOME!

I was trying to make the decision between an A-A, Harman and an AHS and I went with the AHS. I considered the A-A, but after visiting AHS in person and getting a personal tour by Jeff, I went with the AHS. According to Jeff, the AHS is designed after the A-A, which may lead one to believe the AHS is a modernized A-A. Yanche did a good job of describing the upgrades/differances. I couldn't add anything to what he said. You could look at the thread titled "Looking for the best coal stoker for my application"

Looking for the Best Coal Stoker for My Applicatiton.

One problem area is the direct drive combustion fan. There is an upgrade option, a belt driven combustion fan, but direct mounting the combustion fan is less costly from a construction standpoint - no pulley's, belt's and associated mounting brackets and hardware required, plus the combustion fan itself is half the size. The direct drive spins at twice the speed and see's heat off the flue gasses which leads to the failure of the high temperature bearing over time. AHS replaces the standard bearing on the mounted side of the electric motor with a high tempature bearing. I elected to go with the direct drive because the bearing is less than $20 and should last 3 - 5 years vrs (if I remember correctly) about $485 for the upgrade.

Hey MXer,

Thanks for your input. I was wondering about the cost to replace the bearing on the direct drive after seeing the 400 plus cost for the belt drive system. $20 for a new bearing - I could buy a lot of bearings for 400 plus! Can anyone about 'half handy' replace a bearing with no problem? Let my quantify 'half handy' - I sharpen my mower blades, have replaced brake pads, rotors and cylinders on a non-abs brake system, change my own light bulbs? I would not attempt an addition to a house, but I replaced a roof on my shed this past summer.

One other question, is the only known trouble spot the bearing wearing out between 3 to 5 years for the direct drive over the belt drive system?

I do plan on getting the temperature control thing for the grate...

Again fellas, thanks a ton for your input and your expertise.

Pret

Hi pret, I'd rate you as 3/4 'handy' . Anyone who can understand the relationships of object and how they interact with each other could change the bearing.

I haven't seen the actual motor and bearing, the main issue may be corrosion or heat changing in clearances of the bearing to the shaft. Ask Jeff if he has suggestions for regular maintenance on the bearing and fan shaft to make the bearing changing easier. I'm sure he can help.

I really envy your guys buying these 'super-boilers'.

Greg L.

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I'll give Jeff a call. 3/4 handy ehh? I think I forgot to mention that usually I end up doing a project three times - like when I began cutting wood this summer with my Husky 350 (nice saw), my chain was a bit too loose and came off while limbing a tree. After putting another one on - buggered up the chain a bit, but fixed it later with a sanding tool - I commenced cutting again, only my chain was on BACKWARDS... I did that on two different occasions in the span of two weeks. You would of thought I'd learned the first time. I'm not sold on the 3/4 handy yet

pret wrote: I was wondering about the cost to replace the bearing on the direct drive after seeing the 400 plus cost for the belt drive system. $20 for a new bearing - I could buy a lot of bearings for 400 plus!

Jeff at AHS estimates an hour of labor to replace the bearing on the direct drive motor. I expect that as a first time experience--or one done only every 5 years it will take a bit more time. There are also a couple of relatively inexpensive tools required to pull the fan from the shaft, to remove the bearings from the motor, and to install the bearings in the motor. Jeff can walk you through the procedure and show you the tools needed when you pick up your boiler.

One other factor to consider is that the belt drive system is reportedly somewhat quieter than the direct drive fan and this may be important depending on where you plan to install the boiler.

The boiler will be in a room in my basement, directly beneath the laundry. Noise could be a factor. There will be some insulation in the first floor joists due to the pex tubing that will be installed for radiant heat. I don't want to hear the motor all winter long.

Can anyone offer specifics on the noise level of the unit in operation?

Thanks Bob for that information - had not considered noise level.

I have the AHS S-130 with the optional belt drive. When I purchased the boiler years ago the belt drive option was not a costly option. The 1/2 HP motor is 1725 RPM and the pulley ratios turns the fan even slower. The fan shaft is supported by two pillow blocks that have ball bearings with grease fittings. I service annually with high temp synthetic grease. The blower is not very noisy at all. What is noisy is the gearbox on the grate motor. Sounds like it doesn't have grease in it, but it's sealed so I don't really know. There is also a very annoying resonance vibration sometimes. It only occurs when the grate motor is running. I suspect it could be damped or eliminated by welding a stout angle iron the the ash pit box where the motor mounts. Since the boiler is not in my home I've just ignored the noise, especially since it only occurs a small fraction of the time. If it were in my home I would have found the cause and fixed it.

MXer says the with the direct drive blower motor the fan is half the size of the belt drive blower. Perhaps the direct drive motor is 3450 RPM vs. the 1725 RPM of the belt drive. I don't know but such a change in the fan diameter would make a drastic change in the air velocity. Fan tip air speed is if I remember correctly is proportional to the square of the radius. My gut feeling is the combustion blower in my AHS is too strong. This would reduce combustion efficiency because it is needlessly blowing hot gases out the flue pipe. I've purchased a Bacharach Fryrite combustion tester off Ebay recently. Next winter I'll make measurements. If necessary I'll change the motor to a variable speed frequency drive and determine the optimum fan speed.

I think anyone with some mechanical skills could change the bearing - maybe not in an hour the first time or two. I'm also working with Jeff to possibly use a direct drive unit with the larger fan and 1725rpm motor. I'm looking at modifing the 56C faced mount to except a larger High Temp bearing or designing a new 56C face hub alltogether. I'll let eveyone know how that progresses.

hi all

I have a ahs s-130 just got done filling her up I have the electronic controller on mine. I love it. I heat 2 house with this and domestic hot water. a week ago I turned down my aquastat to 165 to see what happens.
as long as my oil boiler does not turn on I will be happy. so far so go. these are a great machine. I have the blower option. I would have just one stupid question I did not ask jeff. when you take the heat shield off what do you use if anything to seal it back up?
the fugi controller makes it easy to monitor whats happening with the actual coal fire. right now here in north central pa I am burning about 50 pounds aday. still cheaper than running the oil boiler. have fun

cougar