Coalgun- Puff backs & Explosions

Bob wrote:

lsayre wrote:

Bob wrote:I think the attached set of instructions, taken from a 2007 AHS Manual, make pretty clear that when AHS says to set at 130 the reference is to SV. When SV is set to 130 then ashing starts when the sensed temperature drops to 120 and stops when sensed temperature rises to 130.

Step 4 says to set it at 140.

Yes--I think that may explain why the controller comes programmed from the factory at 140. But if you read the text about actual settings to use during operation it says: "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 firebox."

This is the way the current manual reads also. The only thing it lacks is the entire section about the Fuji control. I still say that until AHS responds to me this is up for interpretation, and I'm leaning in a different direction as to the interpretation.

i dont think they would tell you to change a temp that your controls doesnt read out, they said set to 130 and can lower to 120, well the boiler gives you the read out of the ashing stop temp not the starting temp so why would they tell you to change a number your boiler doesnt give you a read out of

a little off subject here but i forgot to ask when it was mentioned how crucial the baro reading is, where do i measure it with the manometer?

Per the response I got from AHS the set value (SV) can be anywhere from 140 degrees to 120 degrees. They suggest leaving it at the factory preset value of SV = 140 unless there are issues with unburned or partially burned coal.

A setting of below 120 degrees is inviting an outfire.

dchartt wrote:a little off subject here but i forgot to ask when it was mentioned how crucial the baro reading is, where do i measure it with the manometer?

I measure it immediately above the smoke pipe connection.

lsayre wrote:Per the response I got from AHS the set value (SV) can be anywhere from 140 degrees to 120 degrees. They suggest leaving it at the factory preset value of SV = 140 unless there are issues with unburned or partially burned coal.

A setting of below 120 degrees is inviting an outfire.

Thanks for posting the response.

I think it is a bit puzzling that AHS makes no mention of the information that has been in the Axeman manual for 50 years--that improper "thickness of the fire" can cause puff-backs and that with an AHS boiler with the thermograte option the way to adjust the thickness of the fire is by changing SV.

I think it is also interesting that another poster in this thread reported operating successfully with SV at 109.

[quote]Per the response I got from AHS the set value (SV) can be anywhere from 140 degrees to 120 degrees. They suggest leaving it at the factory preset value of SV = 140 unless there are issues with unburned or partially burned coal.
/quote]
Ok 120 to 140, got it but my experience has been that setting it at 120 doesn't resolve any issues with unburned coal. It does however seem to resolve over heating or should I say overshooting the hi limit set point (as bad) in milder weather as a result of having a "thinner" hot bed of coal" near the top of the chamber verses the deeper bed with the SV set at 140℉
At least that's been my take on it so far.
I'm still learning too though.

Just a crazy thought from an EFM guy.....has anyone tried running a repeat-cycle timer to keep the fire "healthy"? AA includes one with their 130 and 260 boilers, AHS does not...just wondering if anyone had installed a timer and noticed an improvement in the burn-out of the ash.

markviii wrote:Just a crazy thought from an EFM guy.....has anyone tried running a repeat-cycle timer to keep the fire "healthy"? AA includes one with their 130 and 260 boilers, AHS does not...just wondering if anyone had installed a timer and noticed an improvement in the burn-out of the ash.

I have and I didn't notice a difference. After reflecting on my experience I think the reason is that AA needs the regular operation to keep the burn chamber full of coal--the repeat timer causes the coal feed mechanism to operate. The AHS, on the other hand, has a gravity feed system and doesn't require any periodic operation to keep the burn chamber full of coal.

Bob wrote:Thanks for posting the response.

I think it is a bit puzzling that AHS makes no mention of the information that has been in the Axeman manual for 50 years--that improper "thickness of the fire" can cause puff-backs and that with an AHS boiler with the thermograte option the way to adjust the thickness of the fire is by changing SV.

Am I understanding this correctly that at SV=140 the fire column should be thicker (less ash bed below the hot coals), and at SV=120 it should be thiner (more ash bed below the hot coals)?

At 140 the grate kicks on when the ash is at 130, -10diff is default can be changed.
At 120 it kicks on at 110.

The way I see it is the cooler the sv the less ashing the thicker the bed gets the cooler it is. In other words in order to get lower sv before ashing the bed has to get thicker and colder.


At 140 get lots of unburned likely because at this temp it takes so long between blower cycles.

I have a feeling its going to take a -10 day to see this thing put in an honest days work.

are any of you getting alot of partial or unburnt coal or just small amounts? i got myself a manometer ordered to tune my draft in just right hopefully this helps with my coal consumption, its seems to be a lot, alot of coal in ashes too

At 140 I get lots unburned, at 120 i get lots of clinkers.

At 140 i cook myself, at this temps in 60's.

My draft is .04.

dchartt wrote:are any of you getting alot of partial or unburnt coal or just small amounts? i got myself a manometer ordered to tune my draft in just right hopefully this helps with my coal consumption, its seems to be a lot, alot of coal in ashes too

Until I take out my next pan of ashes I won't know for sure, but I've noticed for the last two days that the level of partially burned and unburned coal in my ashes seems to be going down. Only time and the colder weather will tell if it will go away completely. I'm at 130 degrees SV on my thermal ash control. It actually seems that raising my SV (thickening my fire) improved my situation.

I believe at low boiler temps a 120 sv works well, at higher temps the higher sv works better.

Cold weather will tell.