Decision between Keystoker and AHS coal gun

Hi guys,

I'm still between a Keystoker boiler, AHS, and Harman VF3000.

I haven't decided if I plan on burning coil in the summer for the domestic, but if I did is the AHS a bad design for this application b/c it's not insulated? It looks the the Keystoker is.

My basemenet is walkout and will be converted to kitchen/livingroom in the next couple of years so a hot basement in th e summer is not an option.....


thanks for your input.....

my 2 cents says go with a EFM 520. The design is simple yet effective, and you can decide how big and where you want the coal bin. It's insulated and can be turned down for summer use. Some guys are still using EFM's built 50 years ago.

e.alleg wrote:my 2 cents says go with a EFM 520. The design is simple yet effective, and you can decide how big and where you want the coal bin. It's insulated and can be turned down for summer use. Some guys are still using EFM's built 50 years ago.

Yes, the only reason I ruled out the EFM is that the location is in a tight spot in my basement and there is NO room for a coal bin unless I block off the path to the washer/dryer or block the stairs going upstairs

The bin can be a 55 gallon plastic drum and it can be on either side of the unit anywhere from 4' away to 16 feet. It's just a matter of adding more or less auger sections and 2" pipe. I've seen pictures of the bin right next to the stoker but it isn't recommended in the manual.

beatle78 wrote:Hi guys,

I'm still between a Keystoker boiler, AHS, and Harman VF3000.

I haven't decided if I plan on burning coil in the summer for the domestic, but if I did is the AHS a bad design for this application b/c it's not insulated? It looks the the Keystoker is.

My basemenet is walkout and will be converted to kitchen/livingroom in the next couple of years so a hot basement in th e summer is not an option.....

The AHS S130 is insulated. It's the A-A boiler that is not insulated. If you are concerned a summer time optimum domestic water system, you want an indirect hot water heater. The water heater is well insulated compared to any boiler. It will store the heated water with little BTU loss. Any boiler, especially those with large water capacities will radiate the boiler water heat into the boiler room. In summer months this is undesirable, especially if you are air conditioning your home. Basically you are heating water with coal (spending $), heating the air, then using the A/C (spending more $). The ideal boiler for summertime domestic water heating is one with a small quantity of water AND can rapidly respond to demand. The small amount of water reduces radiated heat loss. The rapid response to demand allows a quick transfer of the BTU's to the well insulated indirect water tank when the hot water heater thermostat call for heat. Then the boiler cools. This is unlike any boiler that has a self contained domestic coil which must maintain the water temperature in the boiler. Some boilers have keep fire circuit that turn on the combustion blower, when there is no demand. The produces some unwanted heat. In my opinion of all the coal boilers on the market the AHS coal gun boiler best meets the criteria I've outlined. Your opinion and mileage my vary.

Winter time conditions are different, the radiated boiler losses heats your home. An optimum coal boiler system will produce domestic hot water cheaper than most other fuels. I hedge to say all because in certain parts of the country natural gas is less expensive than coal for domestic hot water production.

Yanche wrote:The AHS S130 is insulated. It's the A-A boiler that is not insulated. If you are concerned a summer time optimum domestic water system, you want an indirect hot water heater. The water heater is well insulated compared to any boiler. It will store the heated water with little BTU loss. Any boiler, especially those with large water capacities will radiate the boiler water heat into the boiler room. In summer months this is undesirable, especially if you are air conditioning your home. Basically you are heating water with coal (spending $), heating the air, then using the A/C (spending more $). The ideal boiler for summertime domestic water heating is one with a small quantity of water AND can rapidly respond to demand. The small amount of water reduces radiated heat loss. The rapid response to demand allows a quick transfer of the BTU's to the well insulated indirect water tank when the hot water heater thermostat call for heat. Then the boiler cools. This is unlike any boiler that has a self contained domestic coil which must maintain the water temperature in the boiler. Some boilers have keep fire circuit that turn on the combustion blower, when there is no demand. The produces some unwanted heat. In my opinion of all the coal boilers on the market the AHS coal gun boiler best meets the criteria I've outlined. Your opinion and mileage my vary.

Winter time conditions are different, the radiated boiler losses heats your home. An optimum coal boiler system will produce domestic hot water cheaper than most other fuels. I hedge to say all because in certain parts of the country natural gas is less expensive than coal for domestic hot water production.

OH OK, thanks Yanche. It seemed weird that such an expensive boiler would not be insulated.

I actually don't use a domestic hot water coil, b/c I have a separate hot water storage tank(insulated) that is a separate Zone on my heating system.

What do you mean by "indirect hot water heater"? Is that what I have?

Thanks,
Jeremy

beatle78 wrote:What do you mean by "indirect hot water heater"? Is that what I have?
Jeremy

Yes. It's called indirect because the fuel first heats the boiler water and then the boiler heats the domestic hot water tank. "Indirectly" via a zone on your boiler. It's the best system and has to performance match. It however, is also the most expensive. You will not need a domestic coil on your coal boiler.

Yanche wrote:

beatle78 wrote:What do you mean by "indirect hot water heater"? Is that what I have?
Jeremy

Yes. It's called indirect because the fuel first heats the boiler water and then the boiler heats the domestic hot water tank. "Indirectly" via a zone on your boiler. It's the best system and has performance match. It however, is also the most expensive. You will not need a domestic coil on your coal boiler.

ok, thanks for setting me straight. So what's your opinion about using the AHS S130 for heating the indirect hot water tank in the summer?

Or should I just let the oil boiler fire up when I get a call for hot water.

On another note, how much did your S130 cost? How long ago did you buy it?

May 4, 2004. $4375, no domestic coil, timer grate control, picked up, self install.

I'd put a hour meter on your oil burner. Measure usage for one summer. Calculate fuel oil usage. Next summer use the coal boiler and compare costs. I measured oil usage last summer. Comparing fuel costs and equipment efficiencies it will be much less expensive to use coal. I plan to do so this summer.

Yanche wrote:May 4, 2007. $4375, no domestic coil, timer grate control, picked up, self install.

I'd put a hour meter on your oil burner. Measure usage for one summer. Calculate fuel oil usage. Next summer use the coal boiler and compare costs. I measured oil usage last summer. Comparing fuel costs and equipment efficiencies it will be much less expensive to use coal. I plan to do so this summer.

Good idea, thanks! By "timer grate control" that means you did not get the "thermal grate control" correct?

Yanche wrote:May 4, 2007. $4375, no domestic coil, timer grate control, picked up, self install.

I'd put a hour meter on your oil burner. Measure usage for one summer. Calculate fuel oil usage. Next summer use the coal boiler and compare costs. I measured oil usage last summer. Comparing fuel costs and equipment efficiencies it will be much less expensive to use coal. I plan to do so this summer.

Yanche,

Is the date a typo? My recollection was that you bought your boiler several years ago. I purchased an AHS-130 in the summer of 2007 at the summer sale price--the base boiler was $4500 plus tax FOB at the plant with the belt driven blower and thermal grate control available as extras.