Newbie with DF520, need some help with tuning...

Hi everyone,

My husband and I just made the switch this year from oil to coal. We splurged and got the DF520, and so far we love it (especially the fuel saving!), but I need some help dialing it in.

For some background we're heating a 3700 sq ft 3 story 1872 brick farmhouse with high ceilings, so we have quite a run for the water to make. The house is split into 3 zones with all 3 thremostats on the first floor. The main thermostat is in the dining room, middle of the house and it very rarely calls for heat (10minutes today in 35-45 deg weather). Then the other thermostats are in office (calls for heat a few hours a day) and in the addition, which calls for heat just about all day in about 45deg weather.

Our settings right now are 4 teeth, 5 air, aquastat is set at 160/200 with a differential of 10. We have it running 2 and 1/2 min every 30min. Do these setting seem okay?

My concern is that I am getting mainly unburnt coal off the front of the fire and ashes off the sides and back. I seem to have very little ash ring and what is there is actually hanging off the sides in big chunks. I just bumped the air from 4 up to 5 based on the manual saying that too little air could cause a small ash ring. That was 24hr ago and there is no difference. What could be causing the unburnt coal mainly in the front?

My other question is in regards to the thermostats...do you think this setup with the main thermostat rarely calling for heat will cause us trouble in the dead of winter? Right now everything is fine and it keep everything at temp (except the upstairs, which always gets cool and we supplement with out pellet stove up there at night). I guess the coal is just running on the aquastat after the water temp drops from circulating to the addition...will this be okay in the really cold weather as well?

Thanks for any suggestions you can give!
Jen

Hey Jen!!! Welcome to the forum. I'm not the real expert, but it sounds like you haven't been pulling your fines lever for 15 seconds every day while the unit is running. If your unit was used it might be that the auger is getting worn. Or the air holes on that side are plugged. You came to the right place. Someone will know. As for your t-stats, Could the wire from your new addition be switched with the wire from your upstairs? Scott

I got the impression that this was a new unit. If it's used, I would say the same as Scott, but I wanted to ask Big Jim about this first before I answered.

Can you fill us in on more details?

Coal quality is also a factor ,along with if its new or used.What size coal are you burning? Increasing air settings is not allways the answer. WE NEED MORE INFO.

It is a new unit, just fired it up last Thursday. We were adjusting settings alot in the beginning, but have let it run at 4 and 4 for about 4 days now and just bumped the air up to 5 yesterday. It is very clear that there is an ash ring around the back and sides, but upfront it is red and burning right up the edge, so a lot of partially burnt coal is coming off.

What other detail can I give you?

Oh and we are dumping the fines every day, not always when it's running, but they are getting consistently dumped. Maybe an air hole issue? How can I check that?

On the subject of the thermostats, we thought about switching them so that the one in the addition was the main, but I don't think that will help the cold upstairs, because the dining room and upstairs are on the same zone and the dining room stays a consistant 70 with very little heat running. I think all that would do is make it feed the coal a lot more to keep the addition (which is very poorly insulated) warm and we would lose a lot of efficiency. We might want to take the main thermostat out of the dining room and put it in the living room, which is not quite as tightly sealed and then it will control the overall temperature a little better. But, I think we'll have to see how the current setup does in the very cold weather before we make any thermostat changes.

Thanks again for the advice!

Pa Dealer wrote:Coal quality is also a factor ,along with if its new or used.What size coal are you burning? Increasing air settings is not allways the answer. WE NEED MORE INFO.

Of the options we were given we bought the better coal. We were told it would burn better and more efficient than the lesser grade. It's rice size.

The change in air did nothing for the unburnt coal, so I agree, there has to be something else. Especially since it's only coming off the front.

Big Jim weighed in. If you are getting coal from the Wilkes-Barre area, there is a source up there that is selling poor quality coal and lots of people have complained about it.

The dark spot can move around in an old unit because of a worn worm. In a new unit, I would say either it's the air rate, the feed rate, or the quality of the coal. Since you have clinkering, I would say it's the quality of the coal, or maybe all three.

Try a different source of coal.

The coal is from Tamaqua and I have 8 ton of it, so switching isn't much of an option. What should I try with feed rate and air to see if it can be improved with this coal? Is it safe to try a slightly lower feed rate, maybe 3? Auger pipe is cold right now, no heat at all in it.

I know that different batches can obviously have some shifts in quality but I run a DF520 as well and I have used coal from both South Tamqua Coal Pockets and from American Premium (just over the creek) with no ill results. I don't know if that gives you piece of mind or not considering you are locked in for 8 tons of it.

It's going to be experimental on the feed and air. It may take days or weeks to find the right setting. Start with 4 teeth and try different air settings from there.

rocketjeremy wrote:I know that different batches can obviously have some shifts in quality but I run a DF520 as well and I have used coal from both South Tamqua Coal Pockets and from American Premium (just over the creek) with no ill results. I don't know if that gives you piece of mind or not considering you are locked in for 8 tons of it.

Yeah, I feel pretty confident with the coal quality, I think we have a little more tuning to do.

Stoker-man...how long should I let it run at each setting before trying another one? Is 24 hr long enough...or should I try waiting it out for several days before another adjustment?

Thanks - Jen

After an hour of running, you should be able to see the effects of the change.

Was it installed by a pro or someone not familar with stokers. Most common settings for rice is 5teeth and 4 1/2 air.

It was installed by a professional and he set it at 4 teeth, 6 1/2 air, running for 1 1/2 min every 30min. Then it got warm out over the weekend and wasn't needed for heat at all and flame started dissappearing and I thought it was going to go out overnight, so I decreased the air to 4 and increased the run time every half hour up to 2 1/2 min. It was still lit in the morning, so I considered the change a success. Now that it's gotten cold again, maybe I need to go back to the original settings, but that air values seems high, doesn't it?

Yes, the air is high. If you run at 4, set the air to 4 also. Keep the same timer setting.