Harman P35i: How do I get my pellets closer to the edge?

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mrjohneel

Feeling the Heat
Dec 8, 2011
275
Suburban Boston
Running my new Harman P35i insert on day 3. I'm burning Barefoots; I have an OAK.
The installer did not do the draft test because he didn't have the tool, but will come back next week.
Anyways, I get a good flame but my pellets are not near the 1 inch front of the burn pot. That is, they're burning well with a high, clear flame about 3 inches from the front -- further down the neck of the pot. Should I be concerned I'm not getting the best efficiency from the stove? I can't find anything in the manual that will help me. Is this a feed rate issue? Any help appreciated.
 
I'm no expert, but there are many on this site, but in my stove the only time the burning pellets approach the front of the burn pot is when the ash builds up after a long burn. As the weather warms and the stove runs cooler, the pellets will be burning no where near the front of the burn pot. So as long as you're warm, there isn't an issue. It's 16 degrees here right now and I have my stove cranked up a little. Feed rate of 4, running in stove mode with the temp set just under 4. My burning pellets are 3 inches from the front of the burn pot.
 
All right, I'm answering my own question here after experimenting for two hours. I increased the feed rate to 5 and for the past hour I've had that sought-after 1 inch line of ash with burning pellets behind it and no burning pellets falling out of the pot. I cranked the heat to 75 and have the blower on low and things seem to be going fine. I'm burning many Barefoots though -- certainly more than a bag a day; but it's cold outside and I still think I'm saving money on oil.
 
You need to talk to your dealer. The one inch thing is only to set the set point for the feed rate. You're going to spend more money on pellets than you would on oil the way your going now.
 
subsailor said:
You need to talk to your dealer. The one inch thing is only to set the set point for the feed rate. You're going to spend more money on pellets than you would on oil the way your going now.
We don't know how many square feet he's keeping at 75 though.
 
I'm heating in total about 1200 feet but my downstairs is only about 900, say. I went to 75 degrees because I wanted to heat up my main room. I've turned it down to 65 now that I'll be going to bed soon. After I reached 75 the Harman cut the flame back and the 1-inch line expanded to 2-3 inches. But when the stove was going full steam on its way to 75, the only setting that brought the pellets to the 1-inch line was 5. Is that wrong?
 
ah, they mythical "1" of ash".......yea, I know it "says that in the manual", but, in reality, its fairly hard to maintain this. Most of the units Ive seen burn a bit further back than that, a couple inches or so. The feed rate is actually a worst-case MAXIMUM timing for the feeder (a setting of 5 basically means at a maximum burn, the feeder has the ability to run roughly 50 secs per minute), with the amount and frequency of feeding being mainly controlled by the ESP probe in the unit. A setting of 5 is pretty high, most often this setting is 3-4, averaging 3-1/2.
 
After reading lbcynya's great "How Your Harman Works" I think I get the purpose of the feed rate (at least I hope so) --it's just as lousyweather says above . But here's what's happening: my installer (without a draft test) set it at about 3.5. My pellets burn a bit further back and leave a pile of ash in front of them that pile up in the burn pot leaving about a 2.5" wall. When I turn the feed rate to 5 -- which I know is high by all accounts -- I get the 1" "ideal" and that wall is pushed off. I want to have the mythical 3.5-4 feed rate. (I don't know why.) Should I be concerned? And more importantly will the draft test affect this at all.
 
The feed rate wont affect the draft setting one bit. Ideally the best time for a reading would have been when the stove was new, and unburned. Now there is residuals which may affect that reading. Evenso, better late than never. The ash accumulation is likely a manifestation of either an elevated salt content in your pellet, or simply a higher amount of ash endemic to the pellet. I dont know of many (any) stoves that shouldnt be running between 3-4. Forget the 1" thing.......
 
I have my p35i set on 4 as a feed rate, 71 degrees on the dial and set to room temp. I am burning about a bag to abag and a 1/4 heating about 1400 sq feet. I do have an ideal setup as this keeps most rooms 72 or above.
 
Here's what works for me with my P35i... When the stove is off, and the room is cool, say 60 degrees or so, I set the Igniter Switch to Automatic, the Feed rate knob to 3 and the temperature dial to 2 or 2.5 and turn the mode selector to Stove Temp at about 60% fan speed. I rarely turn the temperature dial beyond 2.5 and the highest I have ever had it in two years is 3. Typically, once the place starts to warm up I turn the temperature dial to 2. Keep in mind that I am using the numbers, not the degree settings on the temperature dial because I am in Stove Temp mode. When we go to bed I might turn it down to 1 or 1.5 to save pellets but keep the place fairly warm.

The only time I may adjust the Feed Rate knob is if I see excessive ash building/clumping up along the front lip of the burn pot, especially in the corners, after 4 or 5 hours of burning. When this happens I like to scrape off the accumulated ash before making any adjustments. To clear the ash off of the front of the burn pot I do the following: First I open the hopper door (this prevents the feed of pellets) for a minute or so to let the fire die down a bit (but not too much, you don't want it to go out), then I turn the convection blower down to minimum (to minimize the amount of smoke that may escape into the room), then I carefully and slowly open the door and quickly scrape the accumulated ash off of the first inch or so of the burn pot with my scraper tool. Then I slowly close the door, close the hopper lid to resume pellet feeding, and turn the convection blower back up to about 60%.

After clearing the ash then adjust your feed rate down slightly, no more than a half a number. Mine is usually on 3 so I might turn it down to 2.75 or so. Now with the freshly cleared front lip of the ash pot you will see how much less the ash accumulates.

Mine is usually happy at a feed rate of 3 and a temperature dial setting of anywhere from 1 to 2.5 or 3. The thread you mentioned above describing how your stove works (and other threads I have read, as well as the manual, say the feed rate should in most cases be somewhere between 3 and 4.

Basically you should not constantly adjust the feed rate knob. Once you find a setting that works with the pellets you are burning and the ash is not accumulating alot in the front of the burn pot, or hot burning pellets are spilling into the ash tray, then you really only need to make adjustments to the convection blower and temperature dial settings. I can easily get 16 to 18 hours out of a bag of pellets with these settings on a fairly cold night like tonight which is about 14 degrees.

For reference, my house was built in 2003, 2x6 construction, double pane windows, 2400 sq. ft., 2 floor, 8 room colonial. With my ceiling fan going in the living room where the stove is to circulate the air the living room is typically 72 or 73, the rest of the floor is around 68, and upstairs maintains 63 or 64 most nights.

The only time I use the Room Temp mode is when the weather is warmer during the shoulder months.

That's what works for me, hope that helps get you started. :)
 
Interesting, Mr. Miser. I've been experimenting with Room Temp but think I'll see what Stove Temp delivers. My biggest problem so far is moving air around my 1928 house. I have a series of room and not an open layout but that's a different issue.
 
The feed rate is used to accomodate the different burn rates that different types (softwood and hardwood) and brands of pellets have and to prevent unburned pellets from falling into the ash pan.

You did the right thing to determine how to set your feed rate. I would leave the feed rate at 5 and forget about it until you change brands or type of pellets. The only time you will get pellets to within 1" of the edge is during a high demand for heat.

If the demand for heat, as determined by the control board, is less than maximum your pellets won't make it to the front of the pot and that is perfectly fine and normal.




mrjohneel said:
After reading lbcynya's great "How Your Harman Works" I think I get the purpose of the feed rate (at least I hope so) --it's just as lousyweather says above . But here's what's happening: my installer (without a draft test) set it at about 3.5. My pellets burn a bit further back and leave a pile of ash in front of them that pile up in the burn pot leaving about a 2.5" wall. When I turn the feed rate to 5 -- which I know is high by all accounts -- I get the 1" "ideal" and that wall is pushed off. I want to have the mythical 3.5-4 feed rate. (I don't know why.) Should I be concerned? And more importantly will the draft test affect this at all.
 
Hello, if 5 worked I'd leave it there and only adjust down in half number increments id the pellets are spilling over. Feed rate doesn't waste pellets as long as they stay in the pot.

I would also resist the urge to try stove temp if room temp is working well. I'm MI it's 14 now and the high will be 32 and sunny. To keep an even temp and not overheat (waste pellets) you'll need to fiddle with the temp setting frequently, so why not let room temp do the work...

Have fun, but keep the basics in mind! :)
 
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