New to Coal Burning

It sounds like you are in good shape. It might be helpful to check the draft with a manometer; it is possible to have too much draft and lose excessive heat up the chimney. If your oil burner has a barometric damper, and IF the oil and coal boilers are on the same flue, then that baro might be affecting the coal draft either for better or for worse.

RB; Thanks for your suggestions. Each appliance has it's own chimney. And since I will be burning both coal and later wood and the chimney for the Harman is roughly 20 FT above the thimble I was strongly advised by a " thermotec" guy against a baro damper, and I can understand why. Instead I installed a MPD to help control draft, especially while burning wood. I know it's not recommend by Harman, but I also believe that it is strictly a liability issue. Got a lot to learn about coal yet, but burning wood in this appliance w/o a MPD would definitely not be cost effective. Not to mention the added ability to help slow down a real hot fire. Have not checked with manometer, but visual observations are that the blue flamed are gently leaning toward exhaust, and no sign of over fire.
Will try to get some pic's out then you can have a better idea
THX
Jim

Until recently have had pretty good lock with Harman sf 160. But, today, an issue developed where I was unable to maintain 170 deg f with circulator running. After 3 weeks I thought I had everything figured out, and now this!!!!! Main draft is full open. idle draft is between 3/16 and 1/4in open MPD is full open, all of a sudden the stove refuses to recover quickly. I loaded till coal was running out the door, and shook till the ash pan was entirely glowing. The only thing I noticed was that the feed door was apparently " settling in" and was not closing very tightly. As the gasket was apparently compressing to a point where there was very little resistance . I tried moving the door in tighter, and could not. It seems secure but not snug. Could this be my problem.
PS it's 0 deg here and I had to light wood stove upstairs just to maintain
Thx
Jim

Sounds to me like your losing your draft. Could be fly ash accumulating in a horizontal run or you may have creosote drying out and falling down the chimney blocking it up.

Do you have a manometer hooked up to monitor draft?

570.JPG[/attachment] Pictures of boiler hook up.
Appreciate the feedback.

The SF160 looks nice! I like!!!

No flu restrictions. And no I do not have a manometer.

Larry, Don't have manometer, however can't figure out why all of a sudden this thing slowed down??? Only thing different is the feed door is not as snug as I think it ought to be. It closes firmly, but not really tightly. Can't move it in or out; it's just snug. Is this a problem??

if you think the load door is not closing tight enough,try to close the spinners tight to compensate for loose door so you don't get too much over air draft,if not already closed.

how imperative is a tight gasket on the feed door?

if it's too loose and letting excessive air in,it will send all your heat up the chimney.Do you have a manometer to measure draft.

EDIT: you should have your secondary spinners almost closed for coal and open for wood

J F Graham wrote:... the feed door was apparently " settling in" and was not closing very tightly. As the gasket was apparently compressing to a point where there was very little resistance

My Harman Mk I did the same thing. I changed the gasket and within a couple weeks the new one compressed the same way. I concluded it was not a problem, as long as it was snug all around.

Does the fire itself look slow, or does it look normal? Are you using a different brand of coal? Just start a new pallet that might be different? Extreme percentage of fines in the coal that are restricting air flow? Is the weather suddenly much colder than it has been (it sure is here!) Is the circulator running constantly due to colder weather, where previously it was intermittent? I wonder if you have just reached the limit of how much heat the unit will produce? If you turn off the circulator temporarily will it come back up to temperature in a reasonable time?

I have spinners on my loader door too but mine is a ds machine stove. I can tell you if mine are opened more than halfway and the ash pan door is just about shut. I will lose most of the heat from under the grate which will cool the bed of coal on the bottom leading to a lost fire. The top is still burning good with the blue ladies dancing but as soon as I close the spinners down I will lose them too and the heat is going down to the point of no fire. This is where I go " Oh crap" and run to get the propane torch and still it in the door to get the fire going again before a big poof happens. Been there and done it twice already. I now close them off and leave the ash pan open for 30 minutes and all is good now. Coal needs air to travel up to the bottom of the grates to get the coals to burn and not over the fire. Now some have let very little air to travel over the fire to burn off the gases but only for a little while and then close them. So if your door is leaking and your spinners are open too then you are getting to much air over the fire. Close the spinners closed and get a new door gasket and you should be okay.

J F Graham wrote:Only thing different is the feed door is not as snug as I think it ought to be. It closes firmly, but not really tightly.

The Mark III has the same door latch. I have on occasion used a hammer to bang in the keeper on the stove body so the door latch is drawn to the stove body more tightly. One decent hit would do it. My theory was the keeper was loosened a little when the thicker gasket was installed and as the gasket compressed it needed an 'adjustment'.

As suggested, You will most likely need a manometer to help diagnose the problem. They are cheap, easy to install and the new information is worth its weight in gold lol.