Loss Of Draft To Stoker

With the warmer weather and the stoker set on a very low burn I woke up one morning recently to find the fire out. It must have happened during the early morning hours. I suspect the outside temperature dropped during the night and the flue was cool as there was not much heat going into it, and the cool air outside was just enough to stop the stove from drafting. As mentioned before I have two other appliances connected to the chimney. The draft pulls through them as well. I feel the solution is to install electrically operated draft doors on the pipes to both of these units so the breeching will not be open to them when they are not operating. One is the oil forced hot air furnace and the other is the oil-fired hot water heater.

Comments?

I would start with the larger appliance. Would the water heater have a 4" pipe? I'm assuming it's much smaller. Isolating the larger pipe might be enough to give you better draft. How do you set the barometric with three appliances? Scott

I installed the Man-O-Meter on the stoker before the baro. Set it to limit the draft to .04.
It opens a little with a full fire in the stoker. If the oil burner on the water heater fires then the draft increases considerably in the flue and the baro for the coal stove will open a little more. It's a chimney on the outside of the house, fieldstone and very thick, so it takes a while to warn it up and it's more sensitive to outside temperature then a chimney run up through a structure.

Remember the draft will increase with the amount of heat fed into the chimney, therefore by having to other appliances connected to the flue I lose temperature into the chimney.

Both oil burning units have 6" pipe connected to them.

For all intents and purposes I can disconnect the pipe to the hot air furnace since I don't use it. I still need the breeching connected to the water heater for high demand situations as it will fire.

Sounds like you have a very unique problem. you probly have put considerable thought into the electric dampers. I would seriously consider controlling them so on a fault they return open. Scott

I thought code required you to have only one appliance in any given flue.

Wood'nCoal wrote:With the warmer weather and the stoker set on a very low burn I woke up one morning recently to find the fire out. It must have happened during the early morning hours. I suspect the outside temperature dropped during the night and the flue was cool as there was not much heat going into it, and the cool air outside was just enough to stop the stove from drafting. As mentioned before I have two other appliances connected to the chimney. The draft pulls through them as well. I feel the solution is to install electrically operated draft doors on the pipes to both of these units so the breeching will not be open to them when they are not operating. One is the oil forced hot air furnace and the other is the oil-fired hot water heater.

Comments?

Yes I have a Comment don't be so cheap Don't set the feed rate so low that you lose the fire
you are not saving that much coal by setting the fed rate that low keep it hot you won't lose the draft did you put on
a coal trol yet or a timer that will help keep the fire and the draft going

KLook wrote:I thought code required you to have only one appliance in any given flue.

Yes, that's what the code calls for. I was going to power vent the coal burner, but since coal is the primary unit I took the easy route. As I said the forced hot air furnace isn't being used and the oil-fired water heater only fires under high demand since the stove has a stainless steel loop in it that heats the water.

I'm going to disconnect the smoke pipe to the furnace and cap it, that should eliminate some of the draft loss.

coal berner wrote: Yes I have a Comment don't be so cheap Don't set the feed rate so low that you lose the fire
you are not saving that much coal by setting the fed rate that low keep it hot you won't lose the draft did you put on
a coal trol yet or a timer that will help keep the fire and the draft going

Yes, I am cheap, but aren't we all?

No Coaltrol or timer yet, JC.

The stove is burning to heat DHW right now, I do need to keep a steady fire going for that, although some heat may be needed today with the forecast high of 53 (was in the 70's yesterday).

Mine hasn't flamed out yet, even though we have had 70+ days. But 30's at night.

I think I have the Coaltrol set to min 7, it's maintaining about 110-120 Degrees on the exhaust and only using less than 1#/hr. still idling along. I only have about 100# left.....so it's won't be long!