Unburned Coal In My S130 Ashpan

What temp is your grate shutting off?

BTW: I never solved the problem with my S130 dumping unburned coal while under light load. My S260 burns the crap out of the coal---regardless of how hard or light I'm running the boiler... Just wish I could resolve the puff backs I keep getting. I'm wondering if I need a draft inducer?

watkinsdr wrote:BTW: I never solved the problem with my S130 dumping unburned coal while under light load. My S260 burns the crap out of the coal---regardless of how hard or light I'm running the boiler... Just wish I could resolve the puff backs I keep getting. I'm wondering if I need a draft inducer?

In your case, since you are seeing little unburnt coal...I would set the grate control a little Lower.
That will thin the hot coals layer and thicken the ash layer. Do a small adjustment and give it a half a day to stabilize, you don't want to over do it.

Too thick of fire layer is one of the leading causes of puff-backs.

What we want is a balance between unburnt coal and puff-backs. Anything too far one way or the other is a problem.

I currently have my S260 PLC SV at the 140 degree "factory setting." You recommend trying a higher setting, i.e. 145-150?

I messed up.

No, I spoke incorrectly...should of said...LOWER

Higher Setting= Lower Fire in combustion tube.

Lower Setting= Higher Fire in combustion tube.

But to repeat myself, we want to balance between no unburnt coal and no puff-backs.

I'll Edit my blunder above.

watkinsdr wrote:I currently have my S260 PLC SV at the 140 degree "factory setting." You recommend trying a higher setting, i.e. 145-150?

I don't run a Coalgun, but it sure seems like a higher setting would result in less ash between the sensor and the burning coal.

watkinsdr wrote:I currently have my S260 PLC SV at the 140 degree "factory setting." You recommend trying a higher setting, i.e. 145-150?

I believe the "factory setting" is 130--not 140.

The following is taken from a 2009 AHS Manual:

"The ash temperature monitoring control incorporates a digital process controller for operating the coal grate motor based on ash temperature in the grate area. This process offers significant advantages, including the following: It maintains active monitoring of grate temperature during periods of low demand. This monitoring, and subsequent cycling of grates, takes place whether the boiler fan operates or not. This control also reduces the likelihood of unburnt coal being dumped into the ash pan.
This control is factory set to 130° F and should not be adjusted to more than 10° F higher or lower than the factory setting for best operation (refer to Appendix G for instructions). When reading the digital readout, PV refers to the process variable, or actual ash temperature reading. SV refers to the setpoint variable, or the temperature setpoint of the control. Based on factory settings, when the temperature of the ash drops to 10° F below the reading indicated at SV the grates will cycle on, operating until ash temperature climbs to the SV value."

The following is taken from a different section of the 2009 Manual:

"THERMO ASH-MONITORING GRATE CONTROL OPERATION
Ash that contains fuel that is not fully combusted will be a higher temperature than ash coming from thoroughly combusted fuel. The Thermo Ash-Monitoring Control automatically monitors the temperature of the ash leaving the coal pot. This provides a feedback mechanism for grate regulation that reduces the need for post install adjustments. Typically, no adjustment other than the factory adjustment is necessary to have the boiler perform at peak power output throughout the burn season (a minor on-site adjustment may be necessary when the boiler is first installed). With the Thermo Ash Monitoring controlled grate, it is possible for the fire to remain lit for days during low usage periods without having to adjust the grate controls by hand, as would be necessary in a timer-based grate control system.
If an ash temperature sensor is used, it should be set at 130° for normal operation. During periods of light demand, reducing the setting to 120° will aid in maintaining the proper level of coal in the coal pot."

You are correct: The AHS manual states the PLC SV "factory setting" is 130 degrees. I haven't touched the PLC on the S260. I'm assuming my SV is 130. I'll double check the PLC when I get home from work...

Since my ash looks so good (don't go there...) I haven't thought about changing the SV for the puff-back problem...

watkinsdr wrote: I haven't thought about changing the SV for the puff-back problem...

I think you should. A lower SV may solve your puff-back problem, it is really easy to try, and within the bounds recommended in the manual (not lower than 120) I think it is a riskless option.

I emailed AHS and asked what can be done to reduce partially burned coal from showing up in the ash pan, and Shawn responded that to reduce the level of partially burned coal in the ash during periods of generally warmer weather the thermal grate temperature setting should be lowered in 5 degree increments, monitoring the results for 4-5 days between changes, but never going below 120 degrees.

I checked my S260 after getting home from work---the SV is set at 140 (untouched from the factory); even though, the manual says 130. Reviewing my old post, I see my old S130 also came from the factory set at 140. I'll try reducing to 130 and see what happens...

Instead of trying to adjust the ash temperature, might you want to try other brands of coal. Harmony seems to give less unburned coal and ashes in my axeman than others I have burned, still a tiny bit of unburned, I have been running all summer up to now and not changed a thing.

thats going to be my next change i think, ive been burning all buckwheat and have lowered the ash temps to the lowest with no sign of less unburnt coal, i have no puff back problems at all,my unburnt coal is quite alot, im going to try burning some pea i think, im hoping for the cold to set in here all day rather than just at night like it has been so i can really see how shes going to run

is it necessary to seal up the bottom of the coalgun? i have my ends sitting on steel plates and fire caulked the ends and sides except where the ash doors are

at 60f+ avg daily temp use sv of 110, diff -10. water 130- 150f
at 50f avg daily temp use sv of 115, diff -10 set blower to kick on at 140f and go to 160-170f.
at 40f avg use sv 120, diff -10 , water 150f - 170f
at 30f avg use sv 125, diff -10, water 155f - 175f
at 20f avg use sv 130, diff -10, water 160f - 180f

draft without blower .02 -.04, with blower .04-.06.

open peep hole on door.

get a field controls fan in a can bring in cold oxygen rich combustion air nearby boiler door, better efficiency, less drafty house, less negative pressure.