To Re-light Or Not to Re-light AHS 130 for the Summer

Threw a mouse on the AnthraKing, some coal and bingo heat. Now I have nearly completed my Ph.D in mechanical engineering and moving onto post grad work on how to prevent puffbacks, soon I will be qualified to own an AA. Guys, it does not have to be so hard. Duck... incoming!!!!!

You may want to use a LOGO programmable relay instead of an electromechanical timer. The difference is like sticking a rock on your gas pedal versus having cruise control.

It will eliminate the out fire problem and save wear and tear on your boiler by only cycling the stoker when it has not run for a given time.

Refer to attached link; EFM 520 Install With Skid/Bulk Bags Feed

Go to the end of the thread.

Here is my experience this week with my EFM boiler.

The LOGO programmable relay is currently set to pull on the stoker every 90 minutes for 90 seconds and pull on the dump zone in 3 hours for 20 minutes. Both of these times will reset to 0 if the boiler has a natural call for stoker run before the time-outs.

I also have it programmed to count the outfire calls and dump calls. So far this week it has had 16 outfire calls and 8 dump calls. Of the 16 outfire calls, most were locked out by the high temp limit, so the stoker did not run.

The EFM so far is easily keeping fire without the outfire timer for 3 hours with a draft of .01 while sitting there. We have yet to hit the really warm days, but so far it looks like an outfire timer stoker call is a waste of time and coal.

The goal is to match your heat load as closely as possible with the boiler btu's. Running the stoker with an outfire timer is adding BTU's when you do not want them. The dump call addresses the real issue that your boiler has sat there raising in water temperature and you need to shed some btu's.

For the dump, the LOGO closes a set of contacts that run in pararell with the thermostat call wires on one of my zone valves.

The LOGO is extremely flexible and easy to use.

The LOGO is a great match for coal boilers as it is so flexible.

It's all about draft. I know an EFM 520 owner that can't go an hour without a timer cycle, otherwise the fire goes out. The other issue is responsiveness. There is a big difference between just keeping the fire alive and having it ready to handle a big draw through the tankless coil.

If you have a strong drafting chimney and an indirect water heater with enough volume, you can "cheat" and run little to no timer cycles.

Rob is right. We are fortunate to have a tall chimney and a superstore hot water tank.

While our EFM has a tankless coil, we never had a need to hook it up.

EFM's using a tankless coil run differently in the summer than one with a separate superstore. I believe the Honeywell L7224 aquastat will run towards the low limit setting with a tankless coil, as it is just water temperature pulling in the stoker. In a system with a superstore, it runs towards the high limit setting.

In our system, the superstore appears to the aquastat as any other heat zone. When the circulator comes on, the boiler gets ready for a big heat load and turns the stoker on. Since the stoker at 3 teeth is putting out more BTU's than needed and it takes a while for the circulator to reheat the superstore, the boiler overruns the call in BTU's and the stoker shuts off on the high limit.

While all this is fine and the domestic hot water needs are satisfied, the result is the boiler temperature is near or above the high limit setting most of the time. This leaves little room for the outfire (hold fire fluff) timer to run the stoker.

This may not be the case for people with a tankless coil, running at the low end of boiler temperature.

Because a superstore has a much larger capacity of hot water, it is not bothered by the 5 minutes of the time it takes a fire that has not been "fluffed" for 1-1/2 hrs to come up to full flame output.

With the recent warmer weather, we did have one outfire, so I moved the dump setting to 10 minutes later than the outfire (hold fire fluff) setting. The outfire is 1 hour 30 minutes and the dump is 1 hour 40 minutes. If the boiler is above the high limit temperature preventing stoking through the outfire timer, it will pull on the dump zone for 20 minutes.

We should probably move this thread to the EFM website, no offense to AHS guys.

Just an update for those reading this thread, I rewired my superstor zone valve off a separate relay so it does not pull in with the triple aquastat on the boiler.

This results in the boiler stoker not coming on until the boiler water temperature reaches the low limit. This made a world of difference with the boiler now running at the low temperature end instead of being near the high limit all the time.

This allows me to run the outfire (hold fire) timer more often with no worry of heating up to the high temp limit. I now am using a setting of 30 minutes for the outfire timer with it running the stoker for 2-1/2 minutes.

The dump timer is set at 40 minutes and it is set to run the stoker for 20 minutes. It never has to come on anymore, saving me fuel.

Both timers will reset to 0 if there is a natural call for heat.

Over the month of June (so far) my AHS S130 has been running on an average of a bit less than 15.5 lbs. per day. I just recently added 192 lbs. of coal to top it off after having gone 12 and a half days without filling it. 192/12.5 = 15.36

Although I bought a repeat cycle timer, I have yet to install it. I'm finding that I may not need to. The rest of this summer will tell me more regarding if it is needed or not for the AHS.

An update on my end, I think the next step will be a LOGO. I have called AHS and Darren talked me through re wiring it to only ash when the blower comes on. That works for 6 to 8 days at a shot and then the fire goes out. When I am burning I am still going through 35 to 50 lbs a day. I leave the windows open at night so I am heating the outdoors but otherwise there would be no call for heat or hot water in the over night. I am hoping that the timer will keep it going for the long haul and reduce the coal consumption. My draft has been running anywhere from -.01 to .025. I would have to get my plumber back out to move the unit as he put it as close to the chimney as possible not allowing for draft inducer. That's my story for now. I will keep you posted.

35-50 lbs per day seems crazy for an S130 with a light load.

I only burned 57 lbs. per day on average in January. As Rob says, 35 to 50 lbs. per day in June is not right!

Is the boiler frequently hitting the dump zone limit and dumping heat? I haven't noticed my boiler tripping the dump zone once this summer.

It sounds like your chimney doesn't have enough draft to sustain the fire. When the fire starts to go out and the aquastat calls for heat, the grate will try to 'ash' the fire and end up pushing unburned coal into the ash pan. Are you planning to hook up a timer?

NWBuilder wrote:My draft has been running anywhere from -.01 to .025.

That range is all the draft I'm seeing for the summer as well (and I had to put aluminum foil over my baro damper to get that much draft), so I don't see draft as being your problem.

His coal may not react the same way...some coal will hold a fire much better than coal from a different source.

NWBuilder, what type of coal are you burning (size and brand)? I've been burning a 50/50 blend of Blaschak pea and Stockton pea.

I am burning Pea from Centralia, I experimented with some Baschack pea as well and had the same results. I also have tape over my barometric damper to get my draft up. I am thinking that a timer is my next step but still don't understand the amount of coal I am going through when my unit is burning. I burned slightly more in the winter when it was at its coldest out, maybe 70 lbs. some days more but I think my settings where off as I left them at what the previous owner had set them at for Spring time running. It was at 120 with 10 degree differential all winter. I figure this year I will go up to 130 with a 5 degree differential and see if that helps. Almost lost the fire tonight after only 3 days running but it finally caught. This is driving me a bit crazy!!