leisure line 110 coal boiler dumping constantly

I have been somewhat stumped by the fact you guys are continually having issue with this. I have never hit the dump zone on mine in a 1 1/2 years of operation. The only thing I haven't factored in is by chance are you guys running on powervents? I have found the best operation is with the low limit at 165* with a 10* diff and the high limit set at 180*. The other difference may be that I don't have my boiler set to start upon a zone calling for heat. I have it set up so that if my water temp temp fall below 155* the zone circulators will shut off until the water comes back above 155*.

That's the same settings that at least I have, but after a full call for heat, just the coals on the grate will raise the boiler temp to 220'ish without any hot water being used. It is not an issue of direct venting, if anything I would figure the direct vent would pull more heat out which would cause it to not get close to the dump temp.

Its just a matter of how to deal with a full bed of hot coals. We are also both burning buck. I'd imagine rice won't heat it up as long after a full call for heat and a grate full of coals.

Yeah I have chimney as vent but that's not the issue I don't know what it could be at this point

Dumping and out-fires...I'd say too much air...cut back on the air.
That will allow better, smaller idle fire that will not go out, show you that your feed is way too much, because now it will be pushing burning coals into the pan.
Once you get less coal in a given time period going across the grate your dumping tendency will go away.
You are just pushing that unit harder than you think.

Back her down!

Thanks for info already with gan down its gotten smaller and running cooler. Im just watching it now

One other question how do you wire circulater to shut off when it drops below certain temp?

A powervent will make the fire go longer before going out without the combustion fan running.

Would someone explain to me what a "Dump Zone " is ?
For all I know , you guys were talking about some bathroom, or an out house, and for a while it made sense to me to keep these places warm when you have excess heat,especially when you have to drop your pants in the freezing winter and have your behind meet the element !
But I think I am just realizing,the more I read, it's not where you would normally take a dump !

klim1972 wrote:One other question how do you wire circulater to shut off when it drops below certain temp?

The circulator should shut off two different ways. Normally it is from the main aquastat. It shuts off at the low boiler setting minus the low differential. So my low is set to 160, and the low diff is 10, so when there is a call for heat it will start the pump at 160, and turn off at 150 (160-10=150).

If it is on the high temp aquastat, it will start the pump at the temp set, and shut off at the differential set on that aquastat. Mine is set to dump at 220 with a 5 degree differential.

I think thats what you were asking.

CoalUserWannabe wrote:Would someone explain to me what a "Dump Zone " is ?

It is a separate high limit aquastat, so that if your boiler reaches a certain temp, it shuts off power to everything, including the feeder and combustion fans, and it will turn on the circulator pump, to pull cooler water into the boiler to cool it down.

Well that helped somewhat but what I meant is , is circulater suppossed to shut of till boiler gets back jp to temp then turn back on. If so mine just runs and even when temp drops really low. I thought there is a way to wire it so it shuts off when its trying to make temp. Then finish satisfying thermostat

So if a dump zone is to take care of excess heat, and if that's normal for coal boilers ,then it's simply some imperfection with boiler design, I mean I don't think you would find dump zone provisions on natural gas boiler, or oil boiler or other non coal fuel boilers !

And if these design were 20 30 40 or more years old, I can understand , due to the slow reaction of solid fuels to burn command, but in today's world with sensors, and iPhone and all other things like cars that park themselves, computers that can understand vocal command, ABS breaks, etc etc, I mean in every technical field you name. Why haven't these coal stove manufacturers made it easy on the rest of us to use coal. They constantly claim innovations, but they still have the same design of years and years ago, don't get me wrong, these are solid and reliable designs, but there is a room for plenty improvements.

You can use a pid controller to slow the feed rate as the temp approached the set point of both the room and the water temp of the boiler to eliminate most overshooting. However the problem for the appliance maufacturers is this. There are virtually no boiler tech/ plumbers who can repair and trouble shoot a pid controller less upload a new runtime and program. So it comes down to the problem that there is insufficient infrastructure availiable to accomplish this at the present time.

CoalUserWannabe wrote:So if a dump zone is to take care of excess heat, and if that's normal for coal boilers ,then it's simply some imperfection with boiler design, I mean I don't think you would find dump zone provisions on natural gas boiler, or oil boiler or other non coal fuel boilers !

It's not a design fault of the boiler. It's installation design fault. There is NO need for a dump zone. Just size the water expansion tank correctly. All solid fuel boilers will over shoot when the aquastat reaches the shut off set point. This will cause the boiler water temperature to rise, especially when no circulator is running. The rising temperature water expands, it must have a place to go or the pressure safety will release. Size the expansion tank correctly and the expanding water will go in it. Upon cooling, by a demand condition or simple radiation off the boiler, the cooling water will exit the expansion tank. REPEAT THERE IS NO NEED FOR A DUMP ZONE ON A PRESSURIZED COAL FIRED BOILER.

jpen1 wrote: REPEAT THERE IS NO NEED FOR A DUMP ZONE ON A PRESSURIZED COAL FIRED BOILER.

I think you saying there is no need for a dump zone is like saying there is not need for a carbon monoxide detector. Of course if you monitor your draft ans make sure everything is running well, then you'll never need one in the sense that you'll never leak carbon monoxide and it will never go off.

The point of a dump zone is a safety mechanism. Some of the boiler parts are rated to 240 degrees. Yes it has a pressure release, so the boiler won't explode, as well as an expansion tank, but that high of a temp of water running through the lines could cause damage to parts. Yes, your stove should never be dumping. If you are you need to make some adjustments.

Its not a design flaw, its just something you need to factor in with this type of heat.

CoalUserWannabe wrote:So if a dump zone is to take care of excess heat, and if that's normal for coal boilers ,then it's simply some imperfection with boiler design, I mean I don't think you would find dump zone provisions on natural gas boiler, or oil boiler or other non coal fuel boilers !

When natural gas / propane / oil reach the high limit they shut off. They produce no more heat. When a solid fuel boiler reaches the high limit, it is still burning and can't be instantly shut off.

Of course there are probably fancy electronics and things you could add to your stove, but the thing that I like about the LL stoves are they are simple. I've read other posts where people need to replace this and that sensor, and multiple combustion fans and such. The more you add to a stove, the more it costs originally and in upkeep.

Thanks yanche, I never really thought about there expansion tank being to small as I have mine oversized if anything. I have always been told that you should go a size big with solid fuel, by some very wise old plumbers and I never really put much thought into it from an engineering stand point. I have big wats etx 90 expansion tank even though on paper it works out that a etx60 would be adequate. Also I might add that depending on your home's water volume you may need to adjust your by-pass valve and if you don't have one with a low mass boiler you need one. You could also install a 20 gallon insulated tank or hot water heater to store some water thus giving yourself more stored energy upon a call for heat which allows the boiler temp to remain more stable and it will absorb the extra energy given off instead of the boiler overshooting so much. Sounds radical but the losses of a good tank are about 1 degree per hour loss and you will lose some pumping back and forth between the tank and the boiler but it no different than my series boiler setup which runs pretty efficiently considering I am pumping 24/7 and when the boiler is just used for domestic hot water I'll only use about 17-18 lbs a day with 3 women in the house.