Update: Harman Accentra keeps shutting down with the same error code: “Incomplete Combustion”

[vferdman]

Hello, everyone. Hope everyone had great holidays in the past few days.

Here is an update on my Harman Accentra 2 problem. To recap, I posted a few weeks ago with a problem of a 6 blink shut-down on my Accentra. I got the stove used a few months ago and it was installed in my house by a professional Harman-trained installer. It is in the corner and has a 90 degree elbow, 3 feet up, 90 degree elbow, 3 feet out through the wall for venting. It uses outside air for combustion intake via a special Harman thimble that combines the intake and vent pipes into one thimble. The vent pipe is 4". The stove kept shutting down with 6 blink error code when the demand for heat was low, but would crank for days on end during high demand periods. So far I have done the following at the suggestions of people in this forum.

1. Thoroughly cleaned the stove several times

2. Replaced the exhaust temperature sensor (ESP)

3. Tried adjusting low draft speed from one extreme to the other

4. Pulled the auger and re-sealed its bearing assembly to the feeder weldment

5. Emptied the hopper and re-sealed the seams in the hopper and the interface between the hopper and the feeder weldment

6. Made sure the intake back draft flapper isn't sticking

7. Always make sure there is no pellet bridge (that would not make for a consistent problem anyway, but still...)

After all that the stove still shuts down with a 6 blink error code when the demand is low. By that I mean the outside temperature getting into say, high 40's and the room temperature on the stove set at 65 degrees. This has happened int he last couple of days. Now that it's well below freezing again, the stove is cranking.

So, I am still at square one and am still looking for suggestions.

Thanks!

 

[bobforsaken]

I think I remember you posting this issue. Did you ever remove the feed to outside air and just let it use inside air? I'm not familiar with the thimble you describe. I'm assuming its something that pulls outside air accross the exhaust in order to heat. If it is leaking, maybe its getting O2 Staved.


Also, when the stove burns out, does it have a burn pot full of pellets or is the burn pot empty?

 

[SmokeyTheBear]

Vladimir,

Could you provide some pictures of your outside vent set up and tell us where in the prevailing wind pattern it is?

 

[THE ROOSTER]

It sounds to me like the stove is shutting down completely and then not starting back up... If you are running in "Room Temp" try switching it to "Stove Temp" then running it as low as it will go and see what happens...

 

[Dougsey]

Try disconnecting the OAK.

I'm thinking some weird back draft that's tripping the vacuum sensor (although I'm not positive that would throw a 6 blink error).

 

[SmokeyTheBear]

Try disconnecting the OAK.

I'm thinking some weird back draft that's tripping the vacuum sensor (although I'm not positive that would throw a 6 blink error).

Loss of vacuum does cause a 6 blink error, that is the reason all of the sealing etc ... was done.

 

[rickwa]

I still think you neeed to buy 3-4 bags of a different brand of pellets to rule fuel out. I know you said you have a few tons of what you have in the garage but when you have a never ending problem you need to start the process of elimination until you come to the problem. there is most likely one thing wrong that is causing all your problems but so far it has been very elusive. I think fuel is about the only thing you havent tried.

 

[investor7952]

Hello, everyone. Hope everyone had great holidays in the past few days.

Here is an update on my Harman Accentra 2 problem. To recap, I posted a few weeks ago with a problem of a 6 blink shut-down on my Accentra. I got the stove used a few months ago and it was installed in my house by a professional Harman-trained installer. It is in the corner and has a 90 degree elbow, 3 feet up, 90 degree elbow, 3 feet out through the wall for venting. It uses outside air for combustion intake via a special Harman thimble that combines the intake and vent pipes into one thimble. The vent pipe is 4". The stove kept shutting down with 6 blink error code when the demand for heat was low, but would crank for days on end during high demand periods. So far I have done the following at the suggestions of people in this forum.

1. Thoroughly cleaned the stove several times

2. Replaced the exhaust temperature sensor (ESP)

3. Tried adjusting low draft speed from one extreme to the other

4. Pulled the auger and re-sealed its bearing assembly to the feeder weldment

5. Emptied the hopper and re-sealed the seams in the hopper and the interface between the hopper and the feeder weldment

6. Made sure the intake back draft flapper isn't sticking

7. Always make sure there is no pellet bridge (that would not make for a consistent problem anyway, but still...)

After all that the stove still shuts down with a 6 blink error code when the demand is low. By that I mean the outside temperature getting into say, high 40's and the room temperature on the stove set at 65 degrees. This has happened int he last couple of days. Now that it's well below freezing again, the stove is cranking.

So, I am still at square one and am still looking for suggestions.

Thanks!

I had this error when stove was installed. It will run ok in stove temp but not room always a 6 blink. Turned out the room temp sensor was pinch and went bad. Put a new one on never had the problem again

 

[GVA]

As I said in the other post......
"There are several things that cause the 6 blink
Board
ESP
no pellets
The stove actually is sensing poor combustion.

ESP has been changed
that leaves the board or no pellets…...Usually

reason for no pellets

Auger motor is bad
bridge in the hopper
bad combustion blower
bad vacuum switch
plugged exhaust
leak in the system
or any combo of the above

we just need to break down all the above
if you’re vac switch opens while the combustion blower is running then
you have a weak draft caused by a failing comb blower, plugged exhaust, leak somewhere in the negative pressure fire box etc…....

It’s possible that you did get a bad ESP replacement….Though doubtfull

If it was a small vacuum leak then turning the draft pot all the way down would trip the stove more frequently I would suspect.

I think that you may have a bit more natural draft right now due to the cold temps that have arrived in Mass, (though i’ve been wrong before)

I think the vac switch IS opening for some reason though"


The stove is shutting down when you're comb blower speed is kicked down to low draft, this is why I think the vac switch is opening and shutting down the stove..
I would look at the comb blower/venting/vac switch/vac tube etc..........Quite possibly a weak combustion blower is the whole problem.....

Stepping on my soapbox here
DRAFT TEST...
Stepping off soapbox now

 

[vferdman]

Thanks, everyone for more suggestions and comments. It has now gotten very cold outside (single digits) and that in the past made the condition go away. So I am now not able to test the various suggestions. I did put the stove in "stove temp" mode and it has been running all night. I am not sure that proves anything, though as it is very cold and the demand is high. The problem usually occurs during low demand periods. I will post pictures of the thimble later, but let me just say that it is a simple device that combines two openings into one fixture, that's all. The intake and exhaust are in no way combined or aggregated. I have tried running with outside air disconnected from the stove and that made no difference. I may try a room temperature sensor, but I am already out $50 on the ESP which I did not need, so I am a bit gun shy about spending more on trial and error. I may try and buzz the room temperature sensor wire for continuity, but other than that I am not sure what could go wrong with it. It is practically indestructible thermistor, isn't it? anyway, I will try most things within reason, but really don't want to throw replacement parts at the problem without some justification.

Thanks!

 

[investor7952]

Thanks, everyone for more suggestions and comments. It has now gotten very cold outside (single digits) and that in the past made the condition go away. So I am now not able to test the various suggestions. I did put the stove in "stove temp" mode and it has been running all night. I am not sure that proves anything, though as it is very cold and the demand is high. The problem usually occurs during low demand periods. I will post pictures of the thimble later, but let me just say that it is a simple device that combines two openings into one fixture, that's all. The intake and exhaust are in no way combined or aggregated. I have tried running with outside air disconnected from the stove and that made no difference. I may try a room temperature sensor, but I am already out $50 on the ESP which I did not need, so I am a bit gun shy about spending more on trial and error. I may try and buzz the room temperature sensor wire for continuity, but other than that I am not sure what could go wrong with it. It is practically indestructible thermistor, isn't it? anyway, I will try most things within reason, but really don't want to throw replacement parts at the problem without some justification.

Thanks!

Trust me its the room sensor it is defective. I have gone through the same a yr ago. Its not the esp its the room sensor. This is why you are running flawless in stove mode because you are by passing the room sensor. Replace the room sensor and your problem is fixed.

 

[Bigjim13]

Thanks, everyone for more suggestions and comments. It has now gotten very cold outside (single digits) and that in the past made the condition go away. So I am now not able to test the various suggestions. I did put the stove in "stove temp" mode and it has been running all night. I am not sure that proves anything, though as it is very cold and the demand is high. The problem usually occurs during low demand periods. I will post pictures of the thimble later, but let me just say that it is a simple device that combines two openings into one fixture, that's all. The intake and exhaust are in no way combined or aggregated. I have tried running with outside air disconnected from the stove and that made no difference. I may try a room temperature sensor, but I am already out $50 on the ESP which I did not need, so I am a bit gun shy about spending more on trial and error. I may try and buzz the room temperature sensor wire for continuity, but other than that I am not sure what could go wrong with it. It is practically indestructible thermistor, isn't it? anyway, I will try most things within reason, but really don't want to throw replacement parts at the problem without some justification.

Thanks!

Trust me its the room sensor it is defective. I have gone through the same a yr ago. Its not the esp its the room sensor. This is why you are running flawless in stove mode because you are by passing the room sensor. Replace the room sensor and your problem is fixed.

One thing to add to this, i had the same problem with my room sensing probe and got a new one from the dealer. I installed it and was still getting the error code. I had the service tech come out to look at it and it turned out that the computer was picking up the sensor but the sensor was reading that it was 99* in the room where the stove is. He reset the comp and (knock on wood) haven't had a prob since.

 

[vferdman]

Trust me its the room sensor it is defective. I have gone through the same a yr ago. Its not the esp its the room sensor. This is why you are running flawless in stove mode because you are by passing the room sensor. Replace the room sensor and your problem is fixed.

Well, I just got the 6 blink shut down in the stove temp mode. Actually I got two shut downs in a row on stove temp. It got a little warmer (around 25-30 outside) and I got a shut down. Been running in stove temp since last night. Ran through the night, but the night was very cold. During the day it got warmer and I got a shut down. That pretty much eliminates the room temperature probe.

 

[vferdman]

One thing to add to this, i had the same problem with my room sensing probe and got a new one from the dealer. I installed it and was still getting the error code. I had the service tech come out to look at it and it turned out that the computer was picking up the sensor but the sensor was reading that it was 99* in the room where the stove is. He reset the comp and (knock on wood) haven't had a prob since.

Now what's that you say about Harman tech resetting the computer? I wonder if that's what I need done. It just seems like a software glitch (I am biased as I used to develop low level software like this). Is there any information on how to reset the computer? I see some dip switches on the PCB, and there is a small header also. So there is a way to connect some instrumentation to this thing.

Also, did you end up keeping the new room temp sensor or did you go back to the old one with everything working fine after the reset? This is very interesting.

 

[investor7952]

A tech should come out with a computer hook up just like when a mechanic plugs a car into a program and it will trouble shoot.

 

[Bigjim13]

One thing to add to this, i had the same problem with my room sensing probe and got a new one from the dealer. I installed it and was still getting the error code. I had the service tech come out to look at it and it turned out that the computer was picking up the sensor but the sensor was reading that it was 99* in the room where the stove is. He reset the comp and (knock on wood) haven't had a prob since.

Now what's that you say about Harman tech resetting the computer? I wonder if that's what I need done. It just seems like a software glitch (I am biased as I used to develop low level software like this). Is there any information on how to reset the computer? I see some dip switches on the PCB, and there is a small header also. So there is a way to connect some instrumentation to this thing.

Also, did you end up keeping the new room temp sensor or did you go back to the old one with everything working fine after the reset? This is very interesting.

After I made about 6 calls to the dealer and got them to believe that I wasn't an idiot who didn't know how to troubleshoot or just plain didn't clean my stove they had a service tech come out to see what the deal was. On my stove, a P61A, on the control board there is a plug in (looks like a USB port) that the tech plugged in his computer to. He could see right away that the room sensor was reading that it was 99* in the room with the stove. He reset it and that was it, here for about 20 min tops. Unfortunately I don't know if you can get the equipment to plug into the stove or the diagnostic software if there is such a thing.

I didn't end up keeping the old probe, they asked me to bring it to the shop so they could look at it before giving me a new one. I assume they either threw it away of sent it back to Harman to get credit for it. I imagine if you call your closest dealer they could do something similar and at least point you in a direction to get this fixed.

I downloaded the manual for the accentra and frankly not much help there (not surprising mine isn't all that helpful either). Anyway the port I was talking about is for a "special DDM monitor supplied exclusively to Harman dealers" so I think you're out of luck there.

 

[maglite67]

The DDM only tells you what the control board is reading and not any special info on how to fix it. I would guess room sensor or your feed rate is to low another problem could be your glass gasket but then you would have a burn problem. Feed rate is not a method to save fuel it's a way to keep your burn pot from overfilling from pellet to pellet. Too little feed not high enough temps and the stove goes out on 6 blinks.

 

[Lousyweather]

The DDM only tells you what the control board is reading and not any special info on how to fix it. I would guess room sensor or your feed rate is to low another problem could be your glass gasket but then you would have a burn problem. Feed rate is not a method to save fuel it's a way to keep your burn pot from overfilling from pellet to pellet. Too little feed not high enough temps and the stove goes out on 6 blinks.

The DDM tells you what the dip switch settings are, which board it is, the voltage to the combustion blower, what the feeder setting is, if the ignitor is on or off, the room temp probe temperature being sensed, what the temp setting is, and the ESP probe temperature being sensed, but yes, its only a helpful diagnostic....it does NOT tell you what to do, and nor can the circuitboard be "reset', so to speak. Also, a draft reading is very nice to have as well........and he does have a burn problem...thats what the 6 blink indicates......

 

[Bigjim13]

The DDM only tells you what the control board is reading and not any special info on how to fix it. I would guess room sensor or your feed rate is to low another problem could be your glass gasket but then you would have a burn problem. Feed rate is not a method to save fuel it's a way to keep your burn pot from overfilling from pellet to pellet. Too little feed not high enough temps and the stove goes out on 6 blinks.

The DDM tells you what the dip switch settings are, which board it is, the voltage to the combustion blower, what the feeder setting is, if the ignitor is on or off, the room temp probe temperature being sensed, what the temp setting is, and the ESP probe temperature being sensed, but yes, its only a helpful diagnostic....it does NOT tell you what to do, and nor can the circuitboard be "reset', so to speak. Also, a draft reading is very nice to have as well........and he does have a burn problem...thats what the 6 blink indicates......

So if the circuitboard can't be reset what would the Harman tech have done in my situation where the room probe was reading that my room was 99*?

 

[Lousyweather]

no, it CANT be reset.......if I plugged my DDM and in, and read the room probe to be reading 99 degrees in a cold room, I'd either think the owner had the probe somewhere warm, OR the probe was defective......and replace the probe...

 

[SmokeyTheBear]

no, it CANT be reset.......if I plugged my DDM and in, and read the room probe to be reading 99 degrees in a cold room, I'd either think the owner had the probe somewhere warm, OR the probe was defective......and replace the probe...

If the room probe were not connected what would the temperature read ?

 

[Lousyweather]

you would get a status light error if in room temp mode, but if the stove was running in stove temp, you would get no error at all....

 

[Bigjim13]

you would get a status light error if in room temp mode, but if the stove was running in stove temp, you would get no error at all....

The stove ran perfectly fine in stove temp, the only issued was in room temp.

 

[SmokeyTheBear]

you would get a status light error if in room temp mode, but if the stove was running in stove temp, you would get no error at all....

Ok, was wondering if it would treat the missing sensor as having reported a temperature that was at one of it's temperature extremes, funny thing about software, if it is snafued you frequently get strange presentations. Vladimir being a software hardware interface person understands where I'm heading with this.

I'm afraid that I must also admit that I've rolled several hundreds of thousands of lines of code, some of which was playing with signal decoding and presentation, and a lot of which was good ole bread and butter large commercial systems, along with more than a little operating system bit twiddling.

 

[Lousyweather]

dating myself here, but I did Fortran programming years ago! ack! Gosh, Im old!

no, if the board is running in stove mode, the room probe can be non-existant, but, in Room Temp mode, if the probe is faulty or non-existant, you should get a "4 blink" error......switching to Stove mode effectively ignores the presence of the room probe, or lack thereof.