Keystoker KB-8, What's It Worth?

I just talked to a former Keystone Mfg. (Keystoker) dealer about a Harman boiler and he said he's got an old Keystoker KB-8 on a pallet out in back of the shop. I'm wondering what something like this is worth considering it's been outside in the weather for a few years. Any idea? Would it be worth it or is it likely to be a mass of solid rusted parts?

KB-8 Which one/type is that? You should have asked him if he wants to get rid of it, and how much he wants.

The KB-8 is a 4-grate water-jacket (hydronic or steam) boiler. Specs say about 163,000 BTUH

Looks to be a smaller version of what most keystokers are. I doubt the controls etc. are any good as I've seen people talking about adding a digital coal-trol to them.

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If it is old, used and sitting in the weather for a couple of years and was not cleaned good before doing so it could be just a big rust bucket. If it looks bad but maybe salvageable I would pay about the price for a thousand pounds of scrap steel. If it looks quite good it could be worth up to a couple hundred dollars or more. That’s if the motor, timer, and aquastats are included and work. If it was never in use and all parts are included and well protected it could be worth maybe a thousand or two. Last I checked a KB-6 was selling for around $4000(or a little under) new here in Pennsylvania. That would be the size smaller than the KB-8. The Inside that is exposed to the fire and ash dust can get pretty ugly and rusted in a short time when exposed to moisture but the inside of the water jacket is most likely like new. Look inside one of the large water coil plates. I there is ugly blistery rust don’t bother with it. If you have or can get the use of a good sand blaster the inside area where the stoker goes can be cleaned up fairly easily.
Bottom line is condition, condition, condition, it could be worthless or up to maybe two thousand or more if it is never used old stock that he got stuck with.

The boiler was used to heat the office area of his showroom (showroom was heated by display stoves etc.). I'll have to ask the conditions under which it was removed from service. He said it had been under a cover (tarp), but that's not exactly weatherproof after a couple of years. I'll definitely want to inspect it and see if the parts are all there.

Maybe not till spring... It's looking more like a couple of hundred bucks than a couple of thousand now that I read your response. Thanks for the insight.

Some other things to consider about the used KB-8, they are heavy! Is the ash door going to work for you? They are made to order for whatever side you want, not convertible like the Harman. That is a rather large boiler unless you have a big house or an old drafty house it could be overkill and be less efficient than a smaller one. I also think that boiler uses a 9” stack and you may or may not be able to reduce to 8” to go into the chimney, the dealer would know, but this could create a problem.
If the price is right and you buy most likely you will have to replace the gaskets in the rear at the two holes for the domestic coil(s). The gaskets are $10 from Keystoker last I checked. If you want a water coil, last I checked they were about $250. I go to Mass. every week and I think it is Federal law that everything in Mass. costs more! The cast Iron parts seem to hold up well. One caution, if the grates look fine don’t remove them. If you do just know you will have to use a sealant like Pyroseal on the top portion between them and where they fit around the air box. You do not want air coming out in this area and encouraging fire at the very top of the grate.
On something like this I look at it as buying work and assuming a risk. (How much will I end up spending to get it working?) If some one wants a lot of money for it let them refurbish it and guarantee it and they can assume the risk.
Hope this helps.

I'm a bit confused at the terminology used on the Keystoker spec sheet. The KB-8 has the following specs: What's the deal with the total capacity and recommended load in square feet? Is that heated area or square feet of baseboard/radiators?

My 1200 square foot house has about 104 feet of 3/4 inch baseboard. If I do my math right, that's only about 16 square feet of radiant heat surface area... Something sounds fishy. How could you be saying it's too large a boiler while the specs say it's more like slightly undersized? Maybe I just don't know the terminology.

But then again, the 315 pound hopper at 30 pounds an hour would be capable (at max output) of emptying the hopper in just over 10 hours, using over 12 times as much coal as I presently use per day. On a thermostat, of course, it would only run when heat was called for and the boiler would idle for extended periods of time... I don't know how much idle time these Keystokers can have, but I wouldn't think more than 15 minutes between 1-2 minute blower/hopper cycles. That would be about 7 to 13 percent duty cycle, meaning (depending on hopper feed rate settings) it could use no less than 2-4 pounds per hour at idle.

What are the timer settings and feet rates for the Keystoker furnaces/boilers? The nearest equivalent warm-air furnace appears to be the A125. Anybody got their settings for one of those handy? How much coal do you use and how large an area do you heat with it?

Thanks for all your help, people.

That boiler would be very large for your application, it could heat a 3-4000 sqft house, depending on insulation, infiltration and windows.

However, if the price is right, since it is a stoker, you can have it run at very low settings, so it may work.

Your size house would typically use a 80-120,000btu boiler or furnace.

Did the dealer ever put a price on the boiler?? You need to take a good look at it, plug it in, make sure the motors run, and the stoker gearbox moves, and do a thorough corrosion inspenction. Check the hopper, if coal was left in it for several years, it will be corroded.

Good luck with it! Let us know what you find, and post photos if you can.

Greg L

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I wonder if the capacity could be reduced by blocking up one of the grates and narrowing the chute area so only 3 of the 4 grates is covered with coal. Well, first off I've got to actually inspect the thing. Who knows, it may be a hunk of scrap-iron and not worth the trouble of transporting it.

He does sell Harman units now though - Been looking at the pellet boilers but I do love coal heat...

The capacity will automatically reduce by the stoker only feeding enough coal to burn an inch or two wide strip at the top of the grates. If the stoker needs more heat, the coal quantity will increase and you will get maybe a 6-8" wide burning strip of coal.

Corrosion first. I don't think you could block a grate without having wasted coal, But Keystoker may be willing to sell as smaller stoker with only three grates.

I'd give keystoker a call and see what they say about it.

Greg L

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I am heating about the same size house with a KB-6. My house is about 100 years old, no insulation and original windows; it’s a bit drafty to say the least. Keystoker just ads a section of grate for each size larger stoker they make. My stoker has three grates. On these cold days the circulator may run for hours almost non stop and the stoker will turn off because it has reached its upper limit (180) on the aquastat. This tells me the stoker is putting out plenty of heat but my house is loosing heat about as fast as the baseboard puts it back.
With proper draft the Keystoker runs one minute out of a fifteen minute rotation of the timer to maintain fire. This timer is adjustable to maybe three out of fifteen or maybe more but one minute is their recommendation if everything is set up properly. The gearbox gives one push of coal every minute.
I found that rice and buckwheat burn about equally as well. I use buckwheat. I have an uncle who uses rice and know of others that use a mixture of both. I use between 2 to 2 ½ 5 gallon buckets of coal a day in this cold weather, one bucket when it’s not so cold. One bucket weighs about 40 pounds I think. I just started keeping records in January so I don’t know what actual usage for fire maintenance would be.
Maybe someone knows for sure about the square feet thing. My thinking always was that they are referring to the cast iron radiators that are sized by square feet per section. One square foot gives off 150 btu/hr at 170 avg. temperature. 150x900=135,000 btu/hr for steam 210 degrees gives 230 btu/hr per square foot. 230x560=128,800 btu/hr. At least the math works. I hope someone who knows for sure chimes in then we will all know for sure.
Give me a PM if you want to know more specifics about my Keystoker.
Information on cast Iron radiators and figuring sqare feeet can be found at http://www.burnham.com look for product info under slenderized radiators

Hmmmm. That's the kind of real-world information I'm looking for. Thanks. My house is all on one level and has great southern exposure so gets some decent solar gain on sunny days (like today). When we had a recent cold spell of near zero nights and 10-20 degree days, I was burning about 40-50 pounds a day in the Hanover (hopper fed stove) but couldn't get the heat to the back end of the house. During moderate weather I use only about 25-30 pounds a day. My ceilings are insulated but the walls are pretty-much zero insulation (R-4 in the livingroom from about 1970).

When I used the oil-burner the pump was on probably 40-50% of the time during cold weather and I used about 1200 gallons of oil for heat and hot water. Although the KB-8 seems a little big for this smaller house, it might just do the trick without overheating if I add a Coal-Trol to it replacing the standard timer-based system. Since there's only 1 motor that does both the combustion air and the pusher, Col-Trol says to contact them first before installing, but they have a Keystoker they're working with so it must be possible.

I'd hope that using the variable speed blower, the KB-8 should be able to be accurately throttled to prevent overshoot. The KB-8 has about 50 percent more thermal mass than the KB-6 so controlling the heat level without overshooting might be more of a problem with a smaller house. I'd hope the Coal-Trol could adjust faster to the conditions than the standard one minute full-blast minimum the timer-based controller does.

Thanks again for everyone's input. I'm anxious to see how this boiler has been stored and whether it's worth refurbishing. I've got access to a bead-blaster that I used to de-rust by present stove but I'd have to borrow or rent a portable sandblaster to do any large parts or get inside the firebox. I'm sure the stoker can be removed and the parts blasted in the cabinet-type blaster but large assemblies would have to be done outdoors with a regular blaster.

Personally I'd not worry about any rust that a bead blaster can touch, that is surface rust. Just cosmetic. The real issue will be if the stoker hopper, feed shoe/paddle/shovel/pusher block or whatever name you want to use is rustied in place, with the adjustment screw rusted up. and the chute where the pusher block is all flakey with rust..

Then there is the price. I think you will burn what you have described just maintaining water temp. I believe you will overall burn more coal than you are now. I'm thinking at least 40-50# per day just to maintain water temp in the boiler. The comfort and ease of operating a stoker stove and even heat throughout the house will have to be considered when deciding if this is worth the money outlay.

I'm sure I could heat my farmhouse with two in-home freestanding stoves or fireplace inserts for less than I am heating it with my remote-building boiler. But having all the dirt, dust etc out in a remote building is a plus, and I can adjust a zone temperature with a thermostat. And all my domestic hot water is 'free' and unlimited. With in-house stoves I would have a significant draw on the whole house bringing in cold outside air and the associated drafts making the house feel colder.

A lot of heat is expended keeping the boiler up to temp when the house is not calling for heat, but I'm willing to pay for this. Even at the extravagant rate of 3 tons per month, I'm saving more than 1/2, mor like 3/4ths on my propane bill.

Take care, Greg L.

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LsFarm wrote:...Snip..Then there is the price. I think you will burn what you have described just maintaining water temp. I believe you will overall burn more coal than you are now. I'm thinking at least 40-50# per day just to maintain water temp in the boiler.
...Snip...
A lot of heat is expended keeping the boiler up to temp when the house is not calling for heat, but I'm willing to pay for this. Even at the extravagant rate of 3 tons per month, I'm saving more than 1/2, mor like 3/4ths on my propane bill.

Greg has identified the key to savings with coal. It's all about eliminating stand-by losses, lost heat when your house doesn't need it. Stoker boilers do it best because it will automatically throttle back when there is no heat demand and keep what heat is produced in the boiler water for future use. The key info you need is what is the minimum coal burn rate needed to keep the fire from going out and how long can you do it. If this is burn rate is acceptable, you can live with an over-sized boiler. You can further reduce heat loss with an indoor/outdoor aquatstat that adjusts the boiler temperature depending on the outdoor temperature.

Yanche

Just got a look at the KB-8. It was flipped on its side with the controls and doors down. The hopper is bent and rusted out. It's basically scrap metal now.

Besides - I would have had to raise the floors in my house to fit it into the cellar - talk about a BIG unit. The hopper was even with the top of the unit, being a semi-gravity feed system. I'd have had to cut a hole in the floor above to add coal to it