AHS S130 Coal Gun : First fire

markviii wrote:I don't think he has the chart recorders and load cells hooked up yet.

A project for next summer perhaps?

I have however used my laser thermometer on the flue, and about 10" out of the boiler the surface temp of the flue is only about 187 degrees. That's much lower than my former wood burning experience.

I also weighed a few 4 gallon buckets of pea, and it comes out to either side of 30 lbs for 4 gallons. So far I have added ~60 lbs of coal just to reach the hopper, and ~210 lbs. to the hopper. The scale is standing by.

Hey Larry:

If you look up into the fire/coal bed from below you'll see the temperature probe which feeds temp information to the PLC. Until the coal bed burns to ash, the PLC process variable (PV) temp will remain high. When the coal burns and turns to ash, the temp read by the probe will finally drop and the stoker motor will run until the PV temp climbs again with fresh coal fed to the fire---everything sounds pretty normal so far. Stoker boilers are a beautiful thing!

Under light load, I'm just interested to see if you have unburned coal in the ashpan; however, this question is way premature right now. Just let the S130 run for a couple of weeks with the factory PLC set variable (SV) temp setting at 140F and see what happens. My S130 was a really fun machine to operate---no obnoxious bad habits like the S260 "beast." Although I finally have the S260 figured out...

BTW: I sold and delivered my S130 to NWBuilder in Norfolk, CT two weeks ago---I'm anxious to hear how he's doing with her.

Nice to see you got her fired up and all is well. With that heater you will be able to enjoy the coming winter. Good luck with her.

My opinion, just because you are ashing less doesn't mean their will be less unburned coal, but possably more, you need air to help with the combustion, and larger (pea) and less ash to restrict air flow. I still don't see how you are reading your ash temp, are you using a thermometer or is it something factory with AHS ?????

AHS offers an ashing option that uses a thermocouple and an electronic control (with a digital readout).

AA130FIREMAN wrote:My opinion, just because you are ashing less doesn't mean their will be less unburned coal, but possably more, you need air to help with the combustion, and larger (pea) and less ash to restrict air flow. I still don't see how you are reading your ash temp, are you using a thermometer or is it something factory with AHS ?????

There is a factory installed Dwyer 16C-2 (Love Controls) digital temperature control that is factory set at 140 degrees. Immediately above the 140 degree setpoint display and within the same control is a similar temperature display that is digitally reading the actual real time ash grate temp. When the grate temp (which is nominally the ash temp) falls below the factory default of 140 degrees this triggers the ash grate motor and sets it in motion. The ash temperature set-point is variable. The manual says to use 130 degrees, or even drop it to 120 degrees in times of low heat demand (like the present). I'm leaving it at the initial 140 degree colder weather setting for awhile though just to see how much unburned coal goes out with the ash once it starts ashing. If I'm seeing to much unburned coal, I'll drop the set-point a couple degrees and observe again.

http://www.dwyer-inst.com/Product/Temperature/Series16C/Ordering

Very nice, Congrats. Enjoy it!

lsayre wrote:

markviii wrote:I don't think he has the chart recorders and load cells hooked up yet.

A project for next summer perhaps?

I have however used my laser thermometer on the flue, and about 10" out of the boiler the surface temp of the flue is only about 187 degrees. That's much lower than my former wood burning experience.

I also weighed a few 4 gallon buckets of pea, and it comes out to either side of 30 lbs for 4 gallons. So far I have added ~60 lbs of coal just to reach the hopper, and ~210 lbs. to the hopper. The scale is standing by.

When I cleaned the 130 out this spring I chucked (gave away) all my winters ashes that I had bagged for someone that wanted them. In cleaning out the boiler I removed the ashes off the grate and did a thoroguh job. This fall, when I started the machine up without ashes on the ash sensor was registering temps that I had never seen in the 3 years I had used the AHS. It reached into the high 450F. I had never seen it get above 225F ever. Turns out that it takes a couple of days to have the coal burn down to the grate and get the asher functioning at lower temps.

As for reading the flue temp... an instant read thermometer inserted into the flue 18 inches above the unit is what is recomended by AHS. Top flue temps in the center should be about 325F max when working at max capacity. I don't think I have ever reached 300F. That may be my coal quality or still the need to fine tune the variables to maximize btu production.

Don't even worry about unburnt coal until if fills the pan the second time. It takes a day until the coal fire fully gets established.

mozz wrote:Don't even worry about unburnt coal until if fills the pan the second time. It takes a day until the coal fire fully gets established.

I just checked, and it has more unburnt coal in the ash pan now than it did after the grates first cycled, so I assume I've had another grate cycle. It looks so good I'm considering just feeding it back into the hopper.

The ash grate just went below the 140 degree mark (I saw 124 degrees) and this time when the ash grate cycled there appeared real ash in the pan. The timeline to our first real ashes in the pan was roughly 26 hours after the first match, and 23 hours after I first turned on the grate switch. It looks like things are continuing along smoothly. The ash grate temperature is back up to about 230 degrees now.

Yahoooo. Gratulations. I think you'll find the AHS130 a breeze to operate. I agree, just let her do her thing for a couple days.
I ran mine through the coldest winter months with the ash temp at 130 and then bumped her down over several days to 120 when the day time highs were in the 50's

I now believe there is at least a 10 degree differential on the thermostatic control for the ash grate motor, and it starts ashing at 130 degrees (or less if the differential is greater than 10 degrees) when the set-point is at 140 degrees. I just watched mine get down to 133 degrees without ashing. The only time I actually caught it actively ashing I saw 124 degrees on the ash grate, so perhaps the differential is 15 degrees.

That's right 10℉ below the set point trips the grate motor into action. Most of the time it will start to ash after the ID fan has been on awhile. (pulling cold air over the thermal couple) Since the TC isn't actually touching the ash there will be a little overshoot in temperature when the grate motor stops and the TC begins to feel the heat rising from the fresh ash.

After she settles in, you won't have enough unburned coal in the ash tub to even mess with. That seems to be more of a issue with how hard she's working rather than what you have the ash temp set at. At least that has been my take on it so far. I'm curious to what others think about that.

I won't be a member of the single match club this season. I just had my first out-fire. I got home from work and my boiler water temp was below 120 degrees, and the grate temp was 74 degrees. The ash bucket was filled to nearly overflowing with un-burnt coal. It got into the 60's here today and with the wife and I at work all day and the programmable thermostats all set to drop down into the low to mid 60's while we are at work, there likely was no demand for heat in any of my zones all day (plus on top of that, no one was here to run any hot water). Could the lack of demand for heat have contributed to my out-fire?

It looks like there will be a learning curve, and a new discipline that we will need to follow in order to tax the boiler and let it fire instead of idling it with no demand for extended periods of time. All tips and pointers are well appreciated.