Just fired up my harman pp38+, it lights up fine but when it's on 1 it doesn't feed enough pellets to keep up with the burn and the flame eventually makes its way almost all the way down to the auger at the bottom of the burn pot. It's not that it doesn't feed, it just doesn't feed enough to keep up with the burn. This is an older unit with the 2 dials. If I keep it around 3 it feeds enough to keep the burn going fairly well. I'm just thinking that whatever regulates the feed rate isn't working correctly. I read somewhere that the esp has something to do with this. I cleaned the esp off and it all shiny. I did it while the exhaust pipe was still warm so when I pulled the esp out the fans all turned off (it thought the stove cooled off) then once I put it back in the fans turned back on (obviously redetecting the exhaust was still warm) I guess my point is that the esp at least seems to be able to tell the stove this so not sure if the esp could be the problem.
Harman pp38+ not feeding enough pellets
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Bioburner
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New pellets or leftovers left in the hopper? Could be the auger has something stuck in the flight and not feeding a full amount, been there and had to pull the auger to get it clear. Or the feed motor is weak and isn't feeding as fast as it should.
New pellets, cleaned the whole thing out before installing. If I put it on turbo it feeds fast as fast as I guess I would expect turbo to feed. I watch the auger mechanism in the back and when it turns it doesn't seem to struggle at all, just seems like it's not feeding as much as frequently as it should.
I also have a fresh air kit installed, could that possibly provide too much air and make it burn too fast?
I also have a fresh air kit installed, could that possibly provide too much air and make it burn too fast?
Bioburner
Moderator
Have you checked the amount of draft with manometer? Your stove may have the exhaust fan turned up to high.
No I have not. All I can say is that if I open the door when it's burning I can feel the suction pulling the door shut again. When you check draft I assume you check it with the blower running? Or do you check it fully turned off?
Bioburner
Moderator
Theres is a test port that the manometer hooks into and installation instructions step one through how and when.
Ok I guess I could give that a shot. I'll have to purchase the manometer first. Could the pellets be burning too quickly? Maybe too much air? Is that where you were going with the exhaust fan being turned up too high? It doesn't seem to have any controls for the exhaust fan. It's either on or off except when I turn the feed control to turbo where it seems to go faster.
Bioburner
Moderator
May have a small adjuster screw on the face of the control board? Look up on youtube about a homemade manometer.
Yes if exhaust fan is running to much for your install it can burn pellets to fast. Hopefully someone with more knowledge of the older 38 can chime in about the adjustment. Would think the install manual would have it.
Yes if exhaust fan is running to much for your install it can burn pellets to fast. Hopefully someone with more knowledge of the older 38 can chime in about the adjustment. Would think the install manual would have it.
I have the same stove, older 2 dials, and when I have the feed rate set to around 1, the stove will feed just enough to keep the fire burning, but you can see the auger. If you are saying that by putting your stove on 1, you can see the auger, but the fire maintains and doesn't burn itself out for lack of fuel, it seems like your stove is functioning fine. Even when my stove is near 2 the flame and pellets are very low in the burn pot.
Last year was my first year with it, and initially the stove wouldn't feed enough pellets to keep a fire going on any setting except turbo. This I diagnosed as an ESP problems, which I replaced and the stove worked fine thereafter. When you place the stove on a 1, that corresponds to a temperature read by the ESP that the stove attempts to maintain via feed rate. For example, if setting 1 corresponds to a lower exhaust temp, i.e. 300 (for example sake), the stove will only feed enough to maintain that temp as read by the ESP. Apparently whatever that temp is, it doesn't take too much burning to get it there.
Last year was my first year with it, and initially the stove wouldn't feed enough pellets to keep a fire going on any setting except turbo. This I diagnosed as an ESP problems, which I replaced and the stove worked fine thereafter. When you place the stove on a 1, that corresponds to a temperature read by the ESP that the stove attempts to maintain via feed rate. For example, if setting 1 corresponds to a lower exhaust temp, i.e. 300 (for example sake), the stove will only feed enough to maintain that temp as read by the ESP. Apparently whatever that temp is, it doesn't take too much burning to get it there.
Ok great. That makes sense. My only issue with that is that when it's burning such a small flame so low in the pot, the air that the blower is pushing into the room starts to get cold. I'm guessing I just need to lower the blower speed at that point then so it doesn't take away the heat at fast as the stove can make it at level 1.
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That's at about 2. Is it normal to have that big pile of ashes all around the end of the burn pot?
So I turned it down to 1 again and turned the blower down to the lowest setting but the stove is not retaining the heat and the blower is turning off.
Bioburner
Moderator
Sounds like its working. Room blower is supposed to shut down when the stove goes to idle mode after cooling it down some. One of the nicer things about the Harman stoves is if the stove calls for more heat it can ramp up faster than a stove that needs to restart.
Normal ! I`ve had my P38 for about 8 yrs now and I can tell you that set at 1-2 the distr. fan WILL cycle on/off since the flame (high) isn`t hot enough to keep the fan running continuously. Mine needs to be on 3 to have the distr. fan run continuously.
I have also replaced the control board a couple yrs ago and the new one operates similarly.
One look at the potentiometers will tell you they are a cheaply made product costing only a few bucks each and probably aren`t consistently accurate from one to the other with regards to dial settings.
I would imagine the dial settings can also change with wear and use. I much prefer the digital settings on my 25pdvc in the workshop.
I have also replaced the control board a couple yrs ago and the new one operates similarly.
One look at the potentiometers will tell you they are a cheaply made product costing only a few bucks each and probably aren`t consistently accurate from one to the other with regards to dial settings.
I would imagine the dial settings can also change with wear and use. I much prefer the digital settings on my 25pdvc in the workshop.
Thanks guys. Do any of you have the Tstat wires hooked to it? Right now mine has spade connectors protecting the terminals. Being that my model is an older one that doesn't have an igniter how does the tstat work? Will it cause the stove to simply go into turbo mode when the room is calling for heat? Will it work with any tstat or are there specific ones that need to be used with pellet stoves?
That pile of ashes at the lip is normal. Doesn't affect performance but I'll pull it down A few times a day if I notice it. As said above, the low flame isn't producing enough heat to keep the blower operating constantly, which is normal. Esp exhaust temp has a minimum that must be maintained before the blower will operate. The older style 2 dial control board is less nuanced than the new boards, but I've never used the thermostat wires so who knows what I am missing. When my stove is one, the blower is at max and feed bet 2.5 and 4 uusually, which eats bet 1 and 2 bags per 24hr period.
Well I read on the tstat. It basically bumps the stove into turbo mode when the tstat calls and then back to the knob setting when it isn't.
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