Discuss Harman 68 Issues

[Tar34]

My H68 has performed very well over the three years I have owned it. It's my only source of heat and I have issues which have just surfaced. I run the stove in manual mode, room temperature. I burn a mixture of corn and pellets. I have been experimenting with the corn to pellet ratio. I had recently brought that ratio down to approximately 25% pellet to 75% corn. I was not happy with this ratio but I have a limited supply of pellet available to I was trying to conserve my stock. I have since returned to a 50/50 ratio. My symptoms. I happened by the stove and noticed the pot was overflowed with corn/pellet and had almost completely stopped burning. I had to clear the pot and restart the stove. I had just cleaned the stove several days before per the Harman book, except the the "fines" in the back of the stove and did not remove the blower cover behind the ash bin. All vent pipe was cleaned as well. It's a short stack vented directly out a window box. Upon restart everything appeared to be back to normal. I have a thermometer on the opposite side of the room and the room temperature will usually keep within one degree of the stove setting. I have always been able to ask for additional heat upon demand, but trying to conserve fuel, I kept temperature in the room around 63 degrees. Last night, again, I woke up and the stove was out, overflowed with corn and pellet. It may have been remnant of lean pellet stock but I don't think so. This time I removed the blower cover and the "fines" cover in the back of the stove. There was some soot in the blower but there exhaust pipe was mostly clear and I was careful with the vacuum not interfere with the sensor. The fines box had significant buildup and that was cleared. Restarted the stove, and again all seemed fine except, I thought, the distribution fan was not turning down after the room came to temperature. I adjusted the the temperature down somewhat the fan began to behave normally automatically to turning up and down to regulate distribution. It has been 18 hrs since I have cleaned and restarted the stove and all has been normal. By normal I mean, in manual mode, room temperature set to 63 and feed rate at #3, the stove has been cycling normally, the 50/50 fuel mixture has been reducing to mostly ash. The burn pile is mostly set back 3 inches from the lip with ash filling the rest. The flame is set back deep in the throat and no fuel buildup. This evening, I decided to warm the room up to 70 degrees. I turned the temperature to 70 and I initially didn't seem to get a response from the stove. Normally I would get a direct increase in feed rate. I gave the stove some time to respond but it seemed content to linger in it's current setting. It would build up a nice hot flame and then turn down to maintenance level with the distribution fan remaining in high mode. Since then I have been able to coax an additional three degrees of room temperature. My temperature sensor behind the stove has not varied in placement since the stove was installed. Quite frankly I'm amazed how synced the stove dial and thermometer across the room has been. I then decided to run in stove temperature mode. Curiously, the fan distribution fan would not come on, no matter the temperature setting. So I reverted back to room temperature so I would have distribution. Mind you, I didn't fool around too much in stove temp setting, so perhaps I didn't let it settle in. I'm worried about loosing heat so I'm being gentle and not forcing the issue.
Any thoughts would be appreciated and I will be sure to respond quickly to any thoughts or suggestions. I apologize if I have not been clear in my description of symptoms or operation of the stove. I am really not clear as to what to expect vis a vis the expected response from the stove and it's actual designed behavior.

 

[Bioburner]

I would at a convenient time clean the ESP by removing it and cleaning it properly with a damp cloth. Soot and ash insulates very well and can lead to various stove control issues as the ESP is the nerve that feeds back the control board-brains. I would do a hard reset by unplugging the stove as well after cleaning the stove.
Good luck

 

[Tar34]

Thanks for your response. I will try that. Absent any blinking lights, any chance a circuit board issue?

 

[MuchoBueno]

When you swItch to stove temp you have to set the temp to 5+ while on MANUAL MODE or just switch to AUTO MODE for the room blower to work.

Edit: Im almost 99% sure about this

 

[Tar34]

Thanks, just discovered the #5 requirement for distribution. Now looking for best access instructions to ESP.

 

[bags]

Welcome! Your ESP is located on the right side of your stove. Take one 1/4" screw out of the top of the right side panel and loosen the bottom two and slide the right side panel out. There is another 1/4" screw that holds your ESP into the exhaust tube. Follow the wires (red on mine) but can be black possibly if your stove is older. The ESP pulls straight out easily and do as Bio suggests above with cleaning. Piece of cake and takes 5-10 minutes total. The screws to remove the right side panel (right looking at the front of your stove) consist of one at the top that needs to come all the way out and two stacked one above the other on the flange towards the front of said panel. Just loosen these enough to slide panel out towards the right.

Now as for your distribution blower not working. Your CB or board is fine and your stove is doing what it should when you are tinkering with the knobs like you have stated. IF you are below 5 or even at 5 sometimes on the temp dial while in constant burn or stove temp (same thing) the distribution blower will shut off IF you are in igniter MANUAL. If you want the distribution blower to throw air while operating in stove temp/constant burn and the temp dial set below 5 then you need to have the igniter toggle flipped UP into AUTO. This will allow the distribution blower to run. MuchoBueno was correct all except the 1%. This is 100% correct.

With the temp dial set anywhere below 5 even down to 1 the distribution blower will blow IF the igniter is in AUTO. You can blow room air with feed rate at 1, Temp dial at 1, while in constant burn/stove temp as long as your igniter is set to AUTO. On the flip side, setting the igniter to MANUAL while in room temp and temp dial wherever your stove will operate a maintenance burn and keep the room temp where you set it. It will not totally burn out and turn off once room temp is met as it will in igniter AUTO while in this set up. It will throttle down but keep a small flame going at all times if in MANUAL IGN., Room Temp. I run this way often and like it because the stove doesn't shut down and get cold and have to reignite when it calls for heat and the temps get ramped back up quicker. Works better in the colder temps and not necessarily during the shoulder seasons where the constant flame might keep you toasty on warmer days but I have found that once it's cooler a little flame never hurt. Just my preference.

Now we will address the piled up burn pot. The P68 DOES NOT run on anything more than a 50% corn and 50% pellet mix or that is the maximum ratio recommended and likely the cause of your problem. Could be the moisture content of the corn too. The P68 is not a 100% corn burning machine nor a 75% corn burning unit. If you want that then you need a PC45 which will do it but most still use a good mix of pellets with them also.

Is your P68 new? If so I have the same unit. Never mind it's 3 years old. What took you so long to show up here? Another mistake but you have now fixed that. They are great if you use them like they are supposed to be used. (50 / 50 corn / pellet max). Read your manual and read a lot here. I can see why it took awhile (3 yrs.) to search out for help because the stove you have pretty much so handles it's own affairs but this forum is a must have for various reasons. Ask questions to save yourself some frustration and costly mistakes.

ALWAYS UNPLUG YOUR STOVE when you mess with it. This includes deep cleans and ESP wipes. These stoves are much less intimidating than what you may think so get to know it. Research it and ask people for help. Many are more than willing to guide and assist. Do you clean your combustion blower fan / impeller behind the plate located behind the ash bin with the hole in it? Have you cleaned the crud out of your ignigter location? Take a look in behind the exhaust blower plate and you will see your ESP back in there a little ways. Dissect your owners manual before you do anything. It's never too late to read that! Good Luck and stay in touch with what you are up to.

 

[F4jock]

First, get a backup heat source.

Second, as Bio said, clean the ESP. You can find it's location and instructions on line or in your manual.

Third, read and understand your instruction manual. You apparently don't understand how your stove was meant to operate.

Forth, once you've read the manual, operate the stove within the manufacturer's parameters. Stop trying to make it do things it was not designed to do.

 

[Tar34]

Welcome! Your ESP is located on the right side of your stove. Take one 1/4" screw out of the top of the right side panel and loosen the bottom two and slide the right side panel out. There is another 1/4" screw that holds your ESP into the exhaust tube. Follow the wires (red on mine) but can be black possibly if your stove is older. The ESP pulls straight out easily and do as Bio suggests above with cleaning. Piece of cake and takes 5-10 minutes total. The screws to remove the right side panel (right looking at the front of your stove) consist of one at the top that needs to come all the way out and two stacked one above the other on the flange towards the front of said panel. Just loosen these enough to slide panel out towards the right.

Now as for your distribution blower not working. Your CB or board is fine and your stove is doing what it should when you are tinkering with the knobs like you have stated. IF you are below 5 or even at 5 sometimes on the temp dial while in constant burn or stove temp (same thing) the distribution blower will shut off IF you are in igniter MANUAL. If you want the distribution blower to throw air while operating in stove temp/constant burn and the temp dial set below 5 then you need to have the igniter toggle flipped UP into AUTO. This will allow the distribution blower to run. MuchoBueno was correct all except the 1%. This is 100% correct.

With the temp dial set anywhere below 5 even down to 1 the distribution blower will blow IF the igniter is in AUTO. You can blow room air with feed rate at 1, Temp dial at 1, while in constant burn/stove temp as long as your igniter is set to AUTO. On the flip side, setting the igniter to MANUAL while in room temp and temp dial wherever your stove will operate a maintenance burn and keep the room temp where you set it. It will not totally burn out and turn off once room temp is met as it will in igniter AUTO while in this set up. It will throttle down but keep a small flame going at all times if in MANUAL IGN., Room Temp. I run this way often and like it because the stove doesn't shut down and get cold and have to reignite when it calls for heat and the temps get ramped back up quicker. Works better in the colder temps and not necessarily during the shoulder seasons where the constant flame might keep you toasty on warmer days but I have found that once it's cooler a little flame never hurt. Just my preference.

Now we will address the piled up burn pot. The P68 DOES NOT run on anything more than a 50% corn and 50% pellet mix or that is the maximum ratio recommended and likely the cause of your problem. Could be the moisture content of the corn too. The P68 is not a 100% corn burning machine nor a 75% corn burning unit. If you want that then you need a PC45 which will do it but most still use a good mix of pellets with them also.

Is your P68 new? If so I have the same unit. Never mind it's 3 years old. What took you so long to show up here? Another mistake but you have now fixed that. They are great if you use them like they are supposed to be used. (50 / 50 corn / pellet max). Read your manual and read a lot here. I can see why it took awhile (3 yrs.) to search out for help because the stove you have pretty much so handles it's own affairs but this forum is a must have for various reasons. Ask questions to save yourself some frustration and costly mistakes.

ALWAYS UNPLUG YOUR STOVE when you mess with it. This includes deep cleans and ESP wipes. These stoves are much less intimidating than what you may think so get to know it. Research it and ask people for help. Many are more than willing to guide and assist. Do you clean your combustion blower fan / impeller behind the plate located behind the ash bin with the hole in it? Have you cleaned the crud out of your ignigter location? Take a look in behind the exhaust blower plate and you will see your ESP back in there a little ways. Dissect your owners manual before you do anything. It's never too late to read that! Good Luck and stay in touch with what you are up to.

Thanks Bags, cogent, concise treatise on the operation of the H68. Of course my fear is damaging the ESP without a replacement in hand but I am marching forward. I will keep all apprised of my progress. Thanks for sharing. I only wish I had discovered this forum earlier.

 

[Tar34]

First, get a backup heat source.

Second, as Bio said, clean the ESP. You can find it's location and instructions on line or in your manual.

Third, read and understand your instruction manual. You apparently don't understand how your stove was meant to operate.

Forth, once you've read the manual, operate the stove within the manufacturer's parameters. Stop trying to make it do things it was not designed to do.

Yes, the manual. Of course it doesn't hurt to ask for the advice from your guardian angels. As far as a back up heat source, that's a story for another column. Hopefully that will come on line within the next two weeks. Now, on to the ESP.

 

[Bioburner]

Since your back there pulling the ESP, might as well pull the fines box cover and clean it. Just make sure to get it back on correct and tight or you'll be back with another issue.

 

[F4jock]

Since your back there pulling the ESP, might as well pull the fines box cover and clean it. Just make sure to get it back on correct and tight or you'll be back with another issue.

Agree x 4

 

[Tar34]

Since your back there pulling the ESP, might as well pull the fines box cover and clean it. Just make sure to get it back on correct and tight or you'll be back with another issue.

Hi bioburner, the fines box was cleaned as mentioned in my first post. Are you saying this is "box" is pressure sensitive?

 

[F4jock]

Hi bioburner, the fines box was cleaned as mentioned in my first post. Are you saying this is "box" is pressure sensitive?

Nah. Bio just has a fetish for tight fines box covers.p

Now, what do you think?

 

[Tar34]

Continuing with the Harman 68 saga. I removed the back panels, brushed and vacuumed the combustion and distribution motors. The distribution fan especially needed cleaning. I did not remove the ESP. The small sheet metal screw which holds the sensor was a little difficult to access. I did not have a proper extension to reach it and I was afraid of stripping the screw head. I will wait until I have the proper extension. I did remove the vent stack plate and was able to access the ESP from there. It wasn't especially dirty and with a rag, I lightly buffed it out and it looked as clean as new. Reassembled the stove. I ran in test mode and all systems were a go. First thing I noticed was the distribution fan doesn't whistle in midrange as it did before. Started in manual mode. I do need a new igniter. Stove started normally, but the stove seems to be stuck a temperature setting just above the manual maintenance level. I have the temperature set to 4 ( 70 deg ) and it seems to holding around #3 ( 65 degrees ). I am measuring room temperature directly across the room approx. 12ft feet from the front of the stove. I have the thermostat directly behind the stove, slightly off to the side approx. 4ft off the floor. In the past, in this configuration, temperature setting within a degree or two matched the stove temperature setting. The flame in the pot is currently low burn. I just increased the Temperature setting to 75 degrees and there just isn't a corresponding increase in feed rate, now set at 4, or temperature.

 

[mr cob]

In my short experience with the harman and corn, the higher the corn mix the worse the stove runs in (ROOM TEMP). This does not seem to apply in (STOVE TEMP). Once the stove settles down in room temp and the flame is deep in the throat, when you adjust the temp/level, the high corn mix does not ignite as fast as a higher pellet % mix does and the auger continues to push the fire off the edge of the plate. I have had no issues running higher % corn in stove temp, except more ash.

 

[Luv2burnPellets]

The ESP must be removed and cleaned as posted earlier. If that didn't solve your problems, than replace the ESP. We cannot stress enough how vital the ESP controls your Harman. Also, you may benefit from replacing the pots on the CB, a simple and inexpensive procedure.

 

[F4jock]

OK. You did well with the cleaning. Now for an experiment cut back or eliminate the corn. I'm a bit confused about how you are running the stove. Room temp, right? Feed rate of 4. ((BTW increasing the feed rate in room temp does not increase the feed rate per se.) Temp dial set at 75. When you say you have the "Thermostat" four feet above the stove do you mean the Room Temp Sensor? In my experience placement of that is critical. Or do you have a thermostat in line? Please clarify before I attempt to go farther. Oh and did you buy the stove new?

 

[Tar34]

I'm burning 50/50 corn to pellet. I'm getting a mostly complete burn after about an hour and a half of running. Attached is photo which shows the depth of the flame and how far the burn is from the edge of the pot. The photo is taken shortly after an addition of fuel to the pot. Difficult to get an accurate image of the flame. Not quite as bright as the image shows. in the forefront is the totality of ash after an hour and a half.

 

[Bioburner]

Hi bioburner, the fines box was cleaned as mentioned in my first post. Are you saying this is "box" is pressure sensitive?

If the fines box leaks air it will throw off the burn and you will be back cleaning a dirty stove shortly.

 

[Tar34]

If the fines box leaks air it will throw off the burn and you will be back cleaning a dirty stove shortly.

Well there you go. Who knew? I did notice the gasket and assumed it should be tight. Dumb luck.

 

[F4jock]

Well there you go. Who knew? I did notice the gasket and assumed it should be tight. Dumb luck.

Is that ash in front? Hard to see

 

[Tar34]

Is that ash in front? Hard to see

yes

 

[F4jock]

Please see my post six above and let me know how you are presently operating.

 

[Tar34]

Please see my post six above and let me know how you are presently operating.

50/50 feed rate 4 room temp mode temperature set at 5 room temp slowly climbing currently 67 degrees fan set low see image above

 

[F4jock]

50/50 feed rate 4 room temp mode temperature set at 5 room temp slowly climbing currently 67 degrees fan set low see image above

Try this. Put some ice cubes in a plastic bag and put your room temp probe between two. Watch what happens to your feed rate after about a minute. Does it pick up? I've found that placement of the room temp probe us critical. Yours may need to be moved. This little experiment will determine if it's working.