Always hot or only when needed?

Always hot or only when needed?

PostBy: ShawnTRD On: Fri Jul 11, 2014 11:09 pm

So I haven't installed my KA6 yet. But when I do will the boiler temperature always be at a set point or will it idle off the timer? I'm sure there will be times I don't need heat and would hate for it to be wasting coal. Maybe this is normal. I just don't know.
ShawnTRD
 
Stoker Coal Boiler: Keystoker KA6 (New in April 2014)
Other Heating: Weil Mclain WGO-2 (Net 75k BTU)

Re: Always hot or only when needed?

PostBy: Richard S. On: Sat Jul 12, 2014 7:38 am

There is going to be an aquastat setting, you might keep it at 160 and 180 in the winter. 160 is the low and it won't let it get below that point. This is how any boiler operates. I don't see how you would have much of a difference between any fuel since they will all be maintaining temperature. The only difference with the coal is longer periods between cycles if there is no heat demand.

That's where the timer comes in especially with bed type stoker. The timer is primarily for the spring/fall/summer to insure it runs and doesn't go out. While idling they use very little coal but it will use coal. I don't know about the Keystokers but you can put your hand on the flue pipe and hold it there with the Van Wert if it's been idling. ;) I'm sure that's the case with the Keystoker too.
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

Re: Always hot or only when needed?

PostBy: ShawnTRD On: Sat Jul 12, 2014 11:11 pm

Richard S. wrote:There is going to be an aquastat setting, you might keep it at 160 and 180 in the winter. 160 is the low and it won't let it get below that point.


See that's not how my current fuel oil boiler works. When the thermostat calls for heat the fuel oil boiler kicks on and comes up to heat. When the heats not needed the fuel oil boiler temp will drop right off. Now I know that easier for the fuel oil because it lights when in demand. But I was hoping the coal boiler could go off the timer just to keep burning then when the thermostat calls for heat have the aquastat take control. I'm sure the temperature would still keep around 120-130 just on the timer (great for DHW). I'm not a plumber, but I don't understand why this can't work. I still need to talk with my uncle who is the plumber. But am I just wishful thinking?

Thanks
ShawnTRD
 
Stoker Coal Boiler: Keystoker KA6 (New in April 2014)
Other Heating: Weil Mclain WGO-2 (Net 75k BTU)

Visit Lehigh Anthracite

Re: Always hot or only when needed?

PostBy: Wiz On: Sun Jul 13, 2014 7:41 am

ShawnTRD wrote:
Richard S. wrote:There is going to be an aquastat setting, you might keep it at 160 and 180 in the winter. 160 is the low and it won't let it get below that point.


See that's not how my current fuel oil boiler works. When the thermostat calls for heat the fuel oil boiler kicks on and comes up to heat. When the heats not needed the fuel oil boiler temp will drop right off. Now I know that easier for the fuel oil because it lights when in demand. But I was hoping the coal boiler could go off the timer just to keep burning then when the thermostat calls for heat have the aquastat take control. I'm sure the temperature would still keep around 120-130 just on the timer (great for DHW). I'm not a plumber, but I don't understand why this can't work. I still need to talk with my uncle who is the plumber. But am I just wishful thinking?

Thanks


Summer settings I'm 130 and 150... Plenty of dhw for family of 4. Set your aquastat 120-140 .... 20 degrees diff is needed.
Wiz
 
Stoker Coal Boiler: Keystoker Ka 6
Coal Size/Type: Casey Junk Coal :(

Re: Always hot or only when needed?

PostBy: coaledsweat On: Sun Jul 13, 2014 8:07 am

Wiz wrote:Summer settings I'm 130 and 150... Plenty of dhw for family of 4. Set your aquastat 120-140 .... 20 degrees diff is needed.

Way to low. You want the water temperature to rise to at least 155*, preferably 160* as oxygen disassociates from water at about 153*. Running temps that low invites Mr Rust in for a feast.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Always hot or only when needed?

PostBy: Rob R. On: Sun Jul 13, 2014 8:43 am

ShawnTRD wrote:When the heats not needed the fuel oil boiler temp will drop right off.


Your oil boiler is setup as "cold start", which means the unit will not maintain temperature when there is no heat call to the aquastat. You could setup the Keystoker the same way, but it would never totally cool off because of the timer cycles. What it WOULD do is increase the response time of the boiler, increase the amount of time that the stoker would have run on a heat call, and possibly allow the boiler to cool enough to allow flue gas condensation.

Your oil boiler holds a couple gallons of water, and has an "instant on" supply of btu's. The KA-6 holds about 50 gallons of water, and the fire is slow to ramp up. Install it the way that Keystoker recommends.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy

Re: Always hot or only when needed?

PostBy: Richard S. On: Sun Jul 13, 2014 9:30 am

ShawnTRD wrote:See that's not how my current fuel oil boiler works. When the thermostat calls for heat the fuel oil boiler kicks on and comes up to heat.


You're not really saving much, typically boilers are most efficient the longer they fire but that is the only place you might see savings. The issue is if you keep a low idle temperature you need to expend more fuel to bring it back up to temperature. Specific considerations with coal is getting a really large fire to bring it up to temperature during low demand is not ideal, (e,g. someone takes a shower but there is no demand for heat). If you have a giant fire and the water is already up to operational temperature it can't absorb as much and a lot of that heat is going to go out of the chimney.

Let's put this into another context, suppose this was a hot water heater. People often turn them off during the day thinking they save something. If the hotwater heater is turned off at 8AM and the temperature drops to 90 by 4PM and you turn it back on you're going to use just about the same amount of fuel bringing it back up to operating temperature had you just maintained it at 140 throughout the day. The only time you start saving any significant money when you turn the hot water heater off is when it reaches the ambient temperature in the room and is no longer losing heat.

You can apply the same thing with coal, that idle fuel consumption is not getting wasted becsue it's being used to maintain the temperature. You don't need to expend a great deal of fuel to bring it back up to operating temperature.

One last thing to note, it's these wild swings in temperatures that usually cause outfires during the Spring and Fall. Perhaps the boiler comes on the morning becsue of a demand for heat, everyone is taking showers etc. It's all fired up and all demand for heat stops. Since you have a large fire the coal that is there is consumed rapidly, it won't run on it's own for hours and the timer is not running enough over those many hours to keep it lit. You would actually be creating this situation keeping it at a low temperature during idle and bringing it up to operational temperature on demand .
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

Re: Always hot or only when needed?

PostBy: Wiz On: Sun Jul 13, 2014 10:33 am

coaledsweat wrote:
Wiz wrote:Summer settings I'm 130 and 150... Plenty of dhw for family of 4. Set your aquastat 120-140 .... 20 degrees diff is needed.

Way to low. You want the water temperature to rise to at least 155*, preferably 160* as oxygen disassociates from water at about 153*. Running temps that low invites Mr Rust in for a feast.


learning something everyday. :D
Wiz
 
Stoker Coal Boiler: Keystoker Ka 6
Coal Size/Type: Casey Junk Coal :(

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