How to dump heat with df 520

No problem!
In addition to checking the draft reading and pulling the fines lever I also check the feed tube near the boiler, at the most it has been moderately warm. Here's my settings:
Air at 5, feed at 3 teeth. Aquastat 210 High/170 Low-15 degree differential. Draft under a full fire runs at -.05" WC. I also have a low temperature cutoff installed that's set at 150 in the event of an outfire, it will stop the stoker from filling the entire ash pan and burn chamber with coal if I'm not around. With the draft problems I have in the hot weather I had several outfires, the cutoff saved me a lot of grief (except for the time I forgot to shut the bypass switch off after relighting the boiler and letting it get up to temperature).

Mark (PA) wrote:You HAVE to adjust your Air up some if the feed tube is too hot to touch.

I think you meant the feed, not the air. Too much air will cause the fire to burn low in the pot, and possibly into the tube. I ran my 520 on 3 teeth with rice for several months, I could easily hold my hand on the auger tube right next to the base. If yours is too hot to touch on 3 teeth, I would definitely run it at 4 teeth & 4 air (assuming you are burning rice coal).

I maintain that the easiest thing to try is reducing the length of the timer cycle.

My timer settings are high due to the draft issue I have. My chimney is fieldstone and massive, on warm days after a cold night the stone holds the cold and the boiler looses draft. In cold winter weather the chimney drafts extremely well.
Typically timer settings are half of the settings I'm currently using, 2 minutes an hour usually.

Yes on the Feed! Thanks Rob...

Sorry Card! Thats what happens when you are in a rush I suppose.

draft readings.
neg.02 at fire door neg.04 at stack . Thanks for all your help I'm going with 4 feed and 4 air and setting back timer . If this doesn’t work maybe I should add room on home and start a laundrymat business and go with 6 teeth. Thanks everyone for your help and be safe

Went with 4 teeth 4 air timer set 1.5 min every half hour, Temp in plex tubing 120, stoker runs 3 hours same amount of time as with 3 teeth 3-1/4 air to heat concrete slap up to temp. All your help corrected the high limit with timer settings ,so no need for dump zone thanks. My concern now is the heat in the feed tube. At 4 or3 teeth same results first 6 inches from boiler tube is hot to touch could only put hand on feed tube momentarily (1 second) (6 to 12 inches from boiler I could rest hand 3-4 seconds, after that is all cool from coupling to 55 gal barrel holding the coal, is this normal ? I think its just getting hot from the boiler heat . On short runs it only gets warm the first 3 inches. After looking at the picture of melted feed tube that stoker man poster. I want to be sure this is not happening Thanks

Rob R. wrote:I maintain that the easiest thing to try is reducing the length of the timer cycle.

cardinal wrote:All your help corrected the high limit with timer settings ,so no need for dump zone thanks.

Excellent.

cardinal wrote:My concern now is the heat in the feed tube. At 4 or3 teeth same results first 6 inches from boiler tube is hot to touch could only put hand on feed tube momentarily (1 second) (6 to 12 inches from boiler I could rest hand 3-4 seconds, after that is all cool from coupling to 55 gal barrel holding the coal, is this normal ?

If the boiler has been running continuously for a few hours, there will be some heat radiating down the auger tube. If during a 20-30 minute run the auger tube stays cool/warm to the touch, I don't think you have anything to worry about.

cardinal wrote:I think its just getting hot from the boiler heat .

Probably. What are you burning for coal?

Look at your fire. If it is burning small and down into the pot, then you should back off the air a little. I seem to get better heat if I can get the fire to go just as big as the brn grates with a complete burn.

Burning Rice Thanks again