Over Heating, Inefficient Burning, Outfires and Lots of Partially Burned Coal in AHS 130

Hi everyone,
I posted part of my problem before under the heading of to re-light or not to relight? Well, I have a number of issues that may all be related so I will give you all the info and hopefully come up with one solution to fix this system. My plumber hooked up my AHS 130 back in January. It worked well or so I thought, I am new to this so I have nothing to compare it with. I have had my pressure release valve go off 6 times and I have had the fire go out 3 times now. My plumber wanted to keep the space used by the boiler to a minimum so my stove pipe converts from 5inch to 6 inch right at the boiler. To the center of the elbow I have 16 inches of stove pipe then 16 inches to where it exits my home at the thimble. Just enough room for a barometric damper. My manometer has never gone above .06 in the winter but reads around .02 consistently. This time of year it seldom gets off of .00. My Aquastat was set at 180 and my dual aqustat was set at 200 hi and low. My plumber installed another on the main pipe which leads to my oil burner and we set that at 180 and used the second floor as my dump zone. Still got prv releases. The asher was set to 120 with a 10 degree differential. Ahs told me to drop my Aquastat to 170 and the asher differential to 5 degrees. Since then I have been going through 70 to 100 pounds of coal, lots un burnt or partially burnt each day until it went out again on Sunday. When I posted before it was suggested that I install a timer on my blower to fluff the fire every so often. Ahs said that the fire should remain lite with just the hot water call every 24 hours. The last outfire happened in the over night after dish washing and 3 showers. I can't see a need to fluff it after it was cooking along so well and went out in 6 or 7 hours. My chimney is clay lined 8 inch and extends 3 feet above the house in the center of the house total chimney height is 38 feet maybe. The next closest building that is of any height is my shop and it is 100 feet from the house so I don't think it is blocking my draft. The guys at AHS also said to re wire it so that the grater only activates when the blower is running. I have not done that as yet but still not sure it will solve all these issues.

To recap, over heating, inefficient burning, outfires and lots of partially burn. From what I have read on here reducing my chimney flue seems like a terrible idea and I don't know if that would solve the problems either. They may all be related or not so that is why I am here asking for some consensus on a direction to go. Thanks in advance everyone, I really want to get bck up and burning these luke warm showers off the oil burner are the pits!!
Ken

Ken, what are you using for an expansion tank? You DID upgrade it or add a second one with the S130 right?

Your chimney sounds like it was built properly, but have you checked the flue to see if it is clear? How about the smoke pipe between the boiler and the thimble? Fly ash can build up in the pipes, so make sure it is clean. Is the cleanout door sealed? Is there anything else connected to the chimney? (water heater, second boiler, etc)

Do you have sufficient make-up air available to the boiler? If the house is tight, you may need to crack a window in the boiler area.

Hi Rob,
My plumber did change out the expansion tank to double its original capacity I believe. The chimney is clear as well as the stove pipe and thimble. When it went out the first time I did the maintanance on the boiler and disassembled the vent pipe as well. I was surprised how little fly ash was in there. The chimney flue is dedicated to the coal boiler only. The clean out door is right on the floor basically and no it is not air tight, kind of loose in the opening actually. The basement is not air tight and I have piped fresh air over to the boiler from the outside, there is always a noticeable air flow at the pipes end so I am certain the boiler has plenty of make up air. When I first light the boiler it runs well for a few days and then quits.

PRV going off is strictly a volume/temperature issue. Expansion tanks are sized based on incomming (intial) fill pressure, maximum system temperature, and system volume. Intial setup of the system and tank is important.

We are talking about the boiler safety relief and not a domestic water pressure/temperature relief valve - Correct?

The short pipe to the chimney is the best possible condition for good draft.

With a 38 foot chimney and a short run to the chimney, you should have enough draft to suck the chrome off of a trailer hitch. ( pardon the analogy).

With the warmer weather, check the adjustment of the barometric without the boiler running but fire still lit. Give yourself a minimum draft of -.02 to -.04 and your fire should be ok.

Over temp is another problem, check how your dump zone works.

Hi Ken,

I am sorry about the issues your'e having and I don't have any answers for you. However, as you already know, you may very well have the finest boiler of its type. Don't get discouraged, please be patient and help will soon follow.

NWBuilder wrote:My plumber did change out the expansion tank to double its original capacity I believe.

Find out what model the tanks are, your total expansion capacity may still not be enough. The other thing to check is the air pressure in each tank, if it is less than the initial static fill pressure (usually 12 psi) of the system the tanks will have reduced capacity before you even light the boiler. Note: You need to drain the system pressure down to zero psi before you check the air pressure in each tank...if you get water out of the schrader valve on the tank it means the tank is bad.

NWBuilder wrote:When I first light the boiler it runs well for a few days and then quits.

That makes it sound like an ashing problem. When the boiler has been running for a while and then shut off, can you see burning coals through the inspection door?

Did I miss it or is there no minimum run-time timer? Say1 minute every 30 minutes....I quickly read the last few posts, and all would seem well, however I would also ask:
Is there outside air or enough interior air available to run this rig?
AHS 130.'never have outfires in my experience, and run very well year round. I was wondering how your timer is set up. Ashing would bee in the ballpark, so I'm still caught up on the run-time timer.....

If you went from a 30 to a 60 Extrol, you might need a 105 floor mounted expansion tank.
Plumbers do not seem to understand that solid fuel appliances do continue to make heat 24/7 unlike oil or gas that cuts the fuel when the aquastat is happy.
You can fix broken, you can fix worn out, you can fix undersized, with enough cash you can even fix UGLY, but you CANNOT fix stupid at any price!

Please stay far from those whom seem to lean that way.

One other thing to look more closely at would be boiler temps in the oil or gas secondary you created. I don't know you lifestyle, but keeping the temps at 180 in the coal and a little less in the secondary may be causing some 'hot suppers'.

Hmm...my AA130 has been cooking along now since November except for a couple oops. I know they are different machines but I have a hopper just like you as well as a separate motorized ashing system. It only ashes when the blower runs.

I don't touch the anthrastat which stays at 140°F. I can look at my aquastat settings and let you know what I'm set at in a few minutes. 180°F high, 150°F low, 10°F differential.

I do however have a run timer. It is set for something like 2 minutes every hour. Seems to be pretty accurate as I've never lost a fire unless the timer stopped or my ashing motor switch was shut off mistakenly.

Unburnt coal is normal this time of year for us unfortunately.

I have no dump zone. The highest temp I've ever seen is around 185°F on the supply side pipe after a 2 minute burn.

My chimney is only about 28' but my clean out door is sealed tightly. Maintain .02" draft at minimum.

The only draw on my boiler for most of the day now is an occasional indirect water heater draw, usually in the morning for showers and evening for dishes or laundry.

I would firstly be concerned about the the draft.. It should never be at .00 and should always be at least a .01 or better or you risk gettin Carbon Monoxide in the home. This could be the root of your out fires too. Its gotta have draft to burn. I would make sure your stove pipe to chimney connection is sealed, clean out door is sealed and anywhere else air could get into the chimney system is sealed... ANd of course there are no obstuctions in the chimney. Also crack a window in the boiler room. Basements tend to have a natural negative pressure that can cannabilize your chimney draw. I agree with the others that your chimney being so tall should be pulling chunks of coal right up thru it or at least have a better draw, even on warm days.

whistlenut wrote:Did I miss it or is there no minimum run-time timer? Say1 minute every 30 minutes....I quickly read the last few posts, and all would seem well, however I would also ask:
Is there outside air or enough interior air available to run this rig?
AHS 130.'never have outfires in my experience, and run very well year round. I was wondering how your timer is set up. Ashing would bee in the ballpark, so I'm still caught up on the run-time timer.....

If you went from a 30 to a 60 Extrol, you might need a 105 floor mounted expansion tank.
Plumbers do not seem to understand that solid fuel appliances do continue to make heat 24/7 unlike oil or gas that cuts the fuel when the aquastat is happy.
You can fix broken, you can fix worn out, you can fix undersized, with enough cash you can even fix UGLY, but you CANNOT fix stupid at any price!

Please stay far from those whom seem to lean that way.

One other thing to look more closely at would be boiler temps in the oil or gas secondary you created. I don't know you lifestyle, but keeping the temps at 180 in the coal and a little less in the secondary may be causing some 'hot suppers'.

Based on other posts I have been involved in, AHS has no minimum run timer and have a different philosophy on controls - good or bad - I haven't figured that out yet. However, my aa-130 went 3 days with the power off during testing it last spring and still fired up. Maybe AHS is onto something. I still use my timer though.

Expansion tanks can be manifolded. If you need more tank, you can add a second. First calculate approximately the system volume. There are several tank sizing programs available. Just make sure you use one that bases it on volume, temperature and fill pressure and doesn't ballpark based on btuh.

I have an AHS and it is idling along superbly so far in this 80 degree weather and sustaining the fire with only an occasional call for heat (perhaps only once a day) due to showers, the dish washer, laundry, and/or the boiler just sitting there and eventually giving off enough heat to the boiler room to bring itself down to 170 degrees (the temperature at which the fan comes on). I have no repeat cycle (hold fire) timer installed yet (though I have one and have the general plans on how to install it, with assistance here from Darren at AHS). I also have my boiler very close to the chimney, and mine also goes immediately to 6" pipe, so all of this sounds very much like your setup. My draft seems overall quite similar to yours also. I have an Extrol #90 expansion tank installed on mine, and my PRV has never let off once. I'm not getting very much unburnt coal in my ashes at present either (far less than I anticipated), though there clearly is some.

I think the key factor is to initiate a good fire in the pot immediately after any start-up (as first noted by Rob to my knowledge), and one means to accomplish that key goal is to run the Dickens out of it right after a start-up by running hot tap water continually for a good while (also as suggested by Rob).

My L4006A is set at 180 degrees (fan comes on at 170, and turns off at 180 degrees), and on the dual Aquastat my fan motor run-away (I.E. L4006A failure) cut-off is set at 200 degrees, and my dump zone is set at 210 degrees.

If your PRV is continually letting off, you may want to check your DHW coil for leaks. The city or well water pressure inside the DHW coil is much higher than normal boiler operating pressure, so any internal leak in the DHW coil (even almost imperceptibly small) would soon over-pressurize the boiler.

Oddly enough, I believe the actual expansion capacity of the Extrol #60 is not much different than that of the #30. I queried Amtrol on this, and as I recall their response was that the #60 is generally for multi story houses, and the #30 is generally for single story houses, but otherwise there is no appreciable expansion capacity difference between them. That's why I chose the #90.

lsayre wrote:Oddly enough, I believe the actual expansion capacity of the Extrol #60 is not much different than that of the #30. I queried Amtrol on this, and their response was that the #60 is generally for multi story houses, and the #30 is generally for single story houses, but otherwise there is no appreciable expansion capacity difference between them. That's why I chose the #90.

I first read this and thought you were mistaken, but I just looked at the Extrol brochure and there is was...2.5 gallons of acceptance volume for the model 30 and 60...the difference is the volume of air within the tank. I have two model 60's on my system, and a 90 on my dad's system. The last EFM I installed got an SX-30V, lots of volume and I tucked it under the basement stairs.

Ken, I usually don't suggest this...but if everything else checks out you might want to try some different coal.

The bottom line is that depending upon the house, replacing a single Extrol #30 with a single Extrol #60 may actually accomplish nothing.