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Posted By forya,
Dec 31, 2011 at 6:18 PM
AWESOME...glad we could help.
Great! Glad it worked out for you!
Glad to hear you are back up and running now that the cold weather is on the way!
My contribution probably won't apply to your stove but might to someone else's stove. My old first-gen Whitfield wouldn't shut it's exhaust fan off after it had cooled down. I'd have to switch the power strip off. Eventually I discovered that when I prodded the wires attached to the heat sensor on the exhaust assembly that it would trip off and on because the fasteners that hold it in place weren't tight and a tight contact is a part of the electrical circuit, so it was opening and closing as I jiggled it. So I wedged a piece of foam-core board against it and part of the pellet housing and now it shuts off every time. So the lesson is that on old stoves (mine is from the early eighties) bolts/nuts can vibrate loose and there goes the electrical path needed to make the sensor work. That probably wouldn't happen on a newer stove.
Hello, Forya /folks
What exactly you mean by "Hard Reset" here ? Do you mean unplug the power and plug it back ? If not, can you outline the detail step
I have exactly same problem with my Harman Accentra. It will not shut down when I turn it to off. when I turn it to off, the status light goes off. power light stay on and motor light and blower stay on. I just bought a used one.
When I turn it to off, I notice it continue to burn till next morning and all pellet are gone from hopper. I repeat the step and make sure the knob is really on "off" position and it still do the same thing.
Can you help me out ? I don't want to waste precious pellet.
#5 should be ON only if it is a red-wire ESP probe.......#5 should be OFF if its a black wire probe. At certain times during thier production, Accentras came with both, but most of the more modern units (non-chain drive Ultralight feeders) had red wire probes.
Either empty out the hopper or let the stove run out of pellets. After the stove has cooled down for and hour or longer unplug the stove from the wall then turn the knob to off. Wait a minute or so and plug it back in. Be sure that the stove gets a complete cleaning including the venting and ESP at the same time.
I repeat the process tonight again. what seem to happen is when I turn it to OFF, the turn off process seems kick in. Status light goes off, feeder slow down, combustion blower off, normal blower stay on. The real problem is no matter how long I wait, the motor (auger) ON and OFF keep feeding in a very very slow pace. Those small amount of pellet feed by auger good enough to keep a small flame around the burning pot live. Such slow on and off auger feeding process never completely stop. So the stove will not totally shut off until all pellet gone. I have no choice to unplug the power to turn it off for now. Otherwise it will burn till the morning and waste a whole bag of pellet again. All lights seems working normal. I appreciate any input on this strange behavior.
(I believe this is not suppose to be. I see Harman Advance model before and the shut down process take no more than 20 minute for flame to go out and then blower continue to cool the stove to finish shut off process.)
You've already explained your problem and I'm trying to help you. I explained what to do in my post directly above yours. If you don't wish to waste pellets, get a five gallon bucket and EMPTY the hopper but it sounds like you unplugged the stove while it was running. This is NEVER a good idea. Anyway, follow the procedure in my previous post. Make sure your stove is CLEAN including your ESP. Also make sure the stove is in Auto not Manual. Let us know how you make out. About 75% of the time a good cleaning and a hard reset will solve the problem. You could have other issues.
ok, i will follow your instruction to do a thorough clean out tonight. BTW, where is ESP exactly located, is it inside the rear exhausted outlet pipe. Do I need to disconnect my pellet pipe to reach it from the back ? Thank you again for your input.
No, you dont necessarily hvae to disconnect the pipe, but you will have to remove the rear body panels. the ESP is inserted in the exhaust path, directly in front of the exhaust flange at about a 45 deg angle with 1 screw. undo screw..carefully pull out probe (no wiggling, no bending) wipe down with wet paper towel, clean exhaust path, reinsert probe. good luck
IMHO, Harman should install a switch as I've mentioned above on all stoves and central heating units to stop the feeding of pellets when needed. One would have to remember to put the switch in the on position prior to powering the unit on.
I can see myself adding this switch in the future too. I can see a few other electric modifications as well.
What about burn back? Shutting the auger off could cause the pellets to continue burning too far back. This is why the feed rate is reduced and the fire is starved of material vs. just turning the auger off. Frankly, I was surprised to see how short the auger is. Not a lot of distance between the hopper and the fire...
When the feed rate is reduced, the fire is starved for pellets, meaning the auger doesn't turn as often, it doesn't mean that the pellets are prevented from entering the auger tube when the auger turns, as long as pellets are in the hopper, pellets will be in the auger tube, feed rate doesn't reduce the quanity of pellets within the auger tube, it reduces the amount of pellets fed into the burnpot. Prior to installing the switch on my boiler to shut the auger down, I used to wait for the boiler to reach the high setting, (180*) manually shut all circulators off, don't use any DHW, wait for the combustion blower to shut down telling me that I could now clean the burnpot, etc. The burnpot cleaning always showed me that with this normal method of shut down, the auger tube always had pellets in it, partially burned pellets at the end of the auger. I think a burn back is possible, doesn't matter if the unit shuts down normally without a switch, or a switch to shut the auger off, both methods stops the auger from running with the same amount of pellets in the auger tube.
This is an ongoing problem for me. After a hard reset I can get it to shut off, but after it shuts off once, it won't do it again. I think the switch is a good idea. where do you put it?
I spent almost 3 hours to thoroughly clean it, scrape some "charcoal" around burning pot. I also clean out the ESP, clean the probe shinny again and put it back. There was so much dirty accumulate on the bottom. It was unbelievable dirty. It looks like the previous owner sold to me had not cleaned it for a long time.
I then put minimum pellet in the hopper and light it up with auto ignition. It burn out pellet about an hour ago. The flame is out, only small amount of ash left on the burning pot. The stove still warm. Even there is no more pellet on the hopper, the feed motor still on and on try to feed some pellet. This last for about 45 minutes. Then the igniter turn on and stay on for the past 20 minutes. The feed motor continue on and off try to feed pellet although there is nothing in the hopper. After about 15 minutes, the igniter stay on but the feed motor no longer turn. Then 5 minutes later, igniter turn off and status light keep flashing. Combustion blower stay on for about another 20 minutes and then completely stop.
I follow your instruction to hard reset it. (unplug power for few minutes, turn the switch to off and plug back power). Then I fill some pellet and ignite it again. After the stove burn for 30 minutes and become hot. I turn it to OFF position. The burning process start to slow down. I wait and wait up to now, for more than an hour. There is no sign the stove tend to shut off. Feed motor on and off keeping minimum pellet fed and keep the flame.
Could it be something else cause this ? I read something on the manual and it say if Jumper 2 is not not connected on the back of the control board. There would be 2 blinks and stove will not shut down. However, I do not see 2 blinks.
Any suggestion is greatly appreciated.
Like I said before, the hard reset and a good cleaning takes care of the issue you are having 75% of the time. This isn't one of them. Hopefully one of the Harman techs here can offer more advice than I can. How old is the stove? I'm thinking you've got an ESP or control board problem.
I would wholeheartedly suggest NOT adding this switch.......might sound like a good idea, but in doing so, you invalidate the UL listing, thereby making it uninsureable, invalidate any warrantee offered by Harman as well, and pretty much guaranteeing any technician SHOULD take one look at your modified stove and turn around, and run away, fast. I guess its your stove, but make these decisions at your own peril, and be prepared to live up to the possible consequences of your actions.
I wonder this is a design problem. I do notice when I turn it to OFF, the Accentra shut down process did kick in. But the key problem is the feeding rate is too fast, fast enough to keep the fire on. I compare Accentra with Advanced model. The Advanced model I observe is once you turn it to "OFF", auger feeding slow down dramatically. Advance model auger do a very small brief turn. The time gap between each turn is much much longer than the Accentra. So Advance model did a good job to starve the fire out. Harman maybe able to address this issue with a better control board.
BTW, I made a mess in the room when I did cleaning. I have a small Craftsman vacuum and it sucks from one each and ash or dust shoot out from the other end.
Any good vacuum you can recommend for pellet stove ? Thanks a million
they have same control board, most likely ESP problem, sometimes it a control board problem, but its not the firmware, its a failure of something. Get a tech to put a DDM on the stove to figure out what temps the ESP is feeding back to the board and you'll have your answers.
Most people complain there stove won't light.
I have a new esp and board. My problem started after I got the new board and esp probe
are you sure the board is set up for your unit? has there been a DDM connected to you unit to ensure that the temp readings are correct?
Yes the ddm was hooked up and everything seems normal. I am waiting for the stove to run out of pellets and shut down, then I am going to look and make sure that my dip switch is in the correct position. I called my dealer, who spoke to Harman, and they said that a dirty stove can insulate it (the probe I guess) and cause it to not shut down, or the dip switch could be in the wrong position. In my case since I have the ESP probe with the RED wires, mine should have dip switch 5 on, and the rest off. I will check this and let everyone know. Also I am going to pull the stove out and clean it real good this weekend. I don't think it is dirty though, because I had this problem right from the beginning of the season when I KNEW the stove was spotless.