New to Coal, What to Buy, Etc.

I have decided to buy a coal stoker boiler to replace my oil burner. My heating system is radiant floor and domestic hot water is via indirect water tank which pulls heat from the boiler primary loop. Chimney is class A, 6", 30'+ tall, drafts extremely well. I refuse to replace it.

The house - is 6 years old, 2,300 sq.ft., 2 floors with great room cathedral ceiling. Insulation is R-35 roof, R-28 walls, R-22 basement walls. The basement (1,400 sq.ft.) will eventually have radiant tubing under a raised subfloor. Backup heat is from 2 wood stoves, one in the basement, one in the living room. Either wood stove will heat the house OK. 3 different heat loss calculations are showing 63,000 - 83,000 BTU/hr which includes the basement. The boiler will be in a basement mechanical room so standby losses will at least heat the basement.

I just started doing research on coal stokers as well as reading this forum. I'm not set on any one brand or model yet. But, based on the physical size of the units, the space available for installing one, and my BTU requirements, I'm leaning towards a Keystoker KAA-2, KA-6, or Harman VF3000. At the risk of repeating questions that have already been answered a million times, here goes...

KAA-2 (76-90K BTU/$3650) - Seems big enough and would operate closer to it's rated capacity which is good for efficiency. I'm not too keen on the small 100 lb. hopper. The 6" breeching matches my chimney without an adapter. My dealer has an unhappy KAA-2 customer complaining that it doesn't heat his small ranch house properly. I would guess that it's not the stove but the rest of his system causing the problem. He is steering me towards the KA-6.

KA-6 (122-144K BTU/$4,5180) - Seems to be more BTU output than what I need but maybe that shouldn't heavily influence my decision? I like the large hopper/less frequent fill/empty cycles. Keystokers burn both rice and buckwheat, even when a bit wet. Dealer suggests a mix (Reading Anthracite). The 8" breeching would require an adapter to 6". Will this unit still perform well with a 6" chimney? Availability of the Keystokers is 10 - 12 weeks.

Harmon VF3000 (95K BTU/$4820) - looks well made, perhaps a notch above the Keystokers in appearance/fit & finish/design details (the pusher mechanism pivots on bronze bearings with oil cups and the cam arm has a ball bearing pushing on the yoke - that's nice! Keystoker is plain steel on steel). 7" breeching would require an adapter which I already have for my oiler's 7" breeching. Again, will the VF3k run well with a 6" chimney? Burns rice coal only! Buckwheat can jam the feeder. Availability - in stock. I can have one tomorrow.

Misc.:

Will the chimney gases/particulates damage my steel roof?

Do I need to run my primary loop at 180 - 190F like I do with my oiler and keep the return loop water above 140F?

I’m sure I’ll have more questions soon. Thanks to all for taking the time to respond.

Hey neighbor, I don't know anything about boiler units(I have a stoker stove) but there are many on here that will help you with your decision. It's not often I see someone on here from my neck of the woods. What dealer are you going through? Just wondering because I want to buy a DHW coil for my stove and I can't seem to find a price for the keystoker coil.

Hi Jeff. Try this link for the coil.

http://www.hilkoil.com/

Hello tightwoods,, welcome to the forum..

Personally I think that for your well insulated home, the Kaa2 or VF3000 will do the job just fine.. if your Harman Dealer is familiar with boilers, and is easy to deal with, this may be the way to go..

The Ka6 would be overkill,, do you have any issues with your current boiler providing enough heat?? what is it's BTU capacity?? How much oil did you burn last several seasons?? Translate this to coal using 180 gallons to a ton of coal..

Personally I'd stay away from Reading coal. Too many problems with quality in the last several years, both from forum members and my own personal experiences.. There are many other sources with much better reputations..

You mention your steel roof.. do you have a painted steel roof?? if so, then you want the top of your chimney to be well above the surface of the steel, and have plenty of height above the closest peak.. I don't think any fly ash could make it's way up you chimney and end up on the steel roofing.. I have not seen any indication of fly ash or rust on my steel roof on my boiler building,, but I have about 6' from the roofing to the chimney cap.

The problem that your dealer mentioned about a Kaa2 not 'heating properly' is most likely what you described,, improper instalation or system setup.. Just understand that an idling coal fired boiler will take about 15-20 minutes to go from an idle fire to a full fire.. unlike a gas or oil boiler which is instant.. So with your radiant floor heat, you must have an anticipator system that reads outside temps and starts the floor heat before the indoor thermostat calls for heat.. there is plenty of lag in an infloor heat system already,, the coal boiler will add more...

Both the Keystoker and Harman are very good units.. and we have many happy members with both brands.. the Harman dealer is the key to the Harman boiler,, if you don't like the dealer,, you cannot contact the factory with questions, only a dealer can contact and get info from the factory.. Keystoker will talk to the customer.

Hope the above helps... Greg L

Greg, thanks for the reply. My Harman dealer is "good people" and I am comfortable with them. They acknowledge the poor customer relations that Harman has with the end user. They stock every part that could possibly break on a VF3000.

My current boiler is a Crown Freeport CT-4 rated for about 120.000 BTU/hr gross. I have been underfiring it by using a .75 nozzle instead of the standard .85. This was done to reduce "short cycling", especially when calling for only DHW. Even with this 12 % reduction in fuel delivery the boiler is more than enough.
I'll do the oil/coal usage comparison.

Another local dealer sells Blaschak coal so I don't have to use Reading.

Steel roof is painted from the factory. I could add another length or two if needed. Time will tell.

Radiant floor - Yes, call for heat is anticipated with a Tekmar programmable controller that senses outdoor temperature.

Harman - I'm strongly leaning towards it but I am concerned when I read on this forum that their warranty is only valid if the installation is done "professionally". I'm a do-it-yourselfer and refuse to pay somebody to do something that I am comfortable doing and would probably do better than most "professionals". I'll see what my dealer says about this.

Thanks again for taking the time to discuss this with me.

Rich

Rich,

I've used a VF3K for the last 4 heating seasons. I'm heating roughly 4,000 sq. ft. very comfortably. The VF3K uses a 6" vent. I know the literature says 7" but also somewhere in the literature it says to use a 6" vent pipe. As far as the warranty, there is very little to be of concern unless the fan motor or feed motor were to fail. I've replaced nothing but the door gaskets on mine. They are vey well built. If your dealer has one in stock, I'd grab it. Harman is back ordered on this boiler until at least 01/09.

Terry

I agree with coalkirk,, if you like your dealer, and he has one in stock,, buy it..

And try this approach about the warantee.. Ask your dealer if he will 'sign off' on the instalation.. Basicly have him inspect it for good quality workmanship and meeting and exceeding code... You can be prepared for his inspection with a cold beer and a list of all the 'special' work you put into the install, 'selling ' him on your quality work..

If he wants to make the sale, he will probably go for the deal..

Best of luck.. Greg L

Terry and Greg, thanks again for your input.

Rich